·编者按·
自闭症
·编者按·
自闭症(autism),又称孤独症或孤独障碍,是广泛性发育障碍的代表性疾病。基本的病理特征是情绪表达困难、社交互动障碍、语言和非语言的沟通有问题,以及日常上常见的,表现出限制的行为与重复的动作,明显的特定兴趣。不能进行正常的语言表达和社交活动,常做一些刻板和重复性的动作和行为。智能发展不平衡,有“孤岛”现象(即某一个方面的智能,如暗记力等特别优秀)。1908年,德国医师Bleuler最早使用自闭症一词描述曾为一般人士但却突然无法再与他人沟通且具有极端孤立的成人精神分裂症患者。1943年,美国医师Kanner首次正式报道了11例具有共同自闭表现的患儿,将其命名为早发性婴儿自闭症(early infantile autism)。
到目前为止,人们对自闭症的致病机制尚未完全阐明。国际上许多的研究者,把自闭症的原因归结为心因性的问题,但其他一些研究者则把自闭症归结为生理学的原因。一般认为,自闭症的致病因素包括遗传因素和环境因素。近几十年来,随着生命科学的发展,对于自闭症的研究和理解也越来越深入,从早期的临床病理层面,逐步深入到细胞以及分子的病理层面,使得人们对于自闭症的发生、病程进展以及治疗有了更全面和精细的了解。目前的研究结果显示:自闭症并不是神经系统的严重的、器质性的损伤,而是与神经系统的发育过程密切相关,其中最重要的则是与神经突触功能有关。
针对不同的影响因素,已有多种对自闭症的干预方法。主要包括生物和非生物疗法。生物疗法包括:抗生素、药物和饮食等。其他治疗方法包括以促进人际关系为基础的疗法、以技巧发展为基础的干预疗法、基于生理学的干预疗法等。虽然这些疗法都有患者在使用,也还没有切实有效的针对核心症状的治疗方法。2016年1 月26日,中科院上海生命科学研究院神经科学研究所仇子龙研究组与该研究所苏州非人灵长类研究平台孙强团队在《自然》杂志发表论文,报道了他们成功构建携带人类自闭症基因MeCP2突变的转基因猴,并且通过分子遗传学与行为学分析,发现MeCP2转基因猴表现出类人类自闭症的刻板行为与社交障碍等行为。该研究首次建立了携带人类自闭症基因的非人灵长类动物模型,为深入研究自闭症的病理与探索可能的治疗干预方法提供了重要基础。
本专题得到仇子龙研究员(中国科学院上海神经科学研究所)、杨广学教授(华东师范大学)、白学军教授(天津师范大学)的大力支持。
·热点数据排行·
截至2016年1月26日,中国知网(CNKI)和Web of Science(WOS)的数据报告显示,以“自闭症”为词条可以检索到的期刊文献分别为2577与 7109条,本专题将相关数据按照:研究机构发文数、作者发文数、期刊发文数、被引用频次进行排行,结果如下。
研究机构发文数量排名(CNKI)
研究机构发文数量排名(WOS)
作者发文数量排名(CNKI)
作者发文数量排名(WOS)
期刊发文数量排名(CNKI)
期刊发文数量排名(WOS)
根据中国知网(CNKI)数据报告,以“自闭症”为词条可以检索到的高被引论文排行结果如下。
国内数据库高被引论文排行
根据Web of Science统计数据,以“自闭症”为词条可以检索到的高被引论文排行结果如下。
国外数据库高被引论文排行
·经典文献推荐·
基于Web of Science检索结果,利用Histcite软件选取LCS(Local Citation Score,本地引用次数)TOP 50文献作为节点进行分析,得到本领域推荐的经典文献如下。
本领域经典文献
Autism as a strongly genetic disorder: Evidence from a british twin study
Bailey, A; Lecouteur, A; Gottesman, I; et al.
来源出版物:Psychological Medicine, 1995, 25(1): 63-77
Face processing occurs outside the fusiform ‘face area’in autism: Evidence from functional MRI
Pierce, K; Muller, RA; Ambrose, J; et al.
来源出版物:Brain, 2001, 124(10): 2059-2073
Mutations of the X-linked genes encoding neuroligins NLGN3 and NLGN4 are associated with autism
Jamain, S; Quach, H; Betancur, C; et al.
来源出版物:Nature Genetics, 2003, 34(1): 27-29
Strong association of de novo copy number mutations with autism
Sebat, J; Lakshmi, B; Malhotra, D; et al.
来源出版物:Science, 2007, 316(5823): 445-449
Mapping autism risk loci using genetic linkage and chromosomal rearrangements
Szatmari, P; Paterson, AD,; Zwaigenbaum, L; et al.
来源出版物:Nature Genetics, 2007, 39(3): 319-328
·推荐综述·
自闭症的病因和治疗方法研究进展
段云峰1,吴晓丽1,2,金锋1
自闭症(autism或autistic disorder)又称孤独症,是一种具有生物基础的发育障碍类疾病,包括一系列复杂的神经发育障碍。最新版的美国精神疾病诊断及统计手册第五版(Diagnostic and Statistical Manual of Mental Disorders-V,DSM-V)已将自闭症的核心症状归结为社交障碍,沟通困难和有限的、重复和刻板的行为。自闭症谱系障碍(autism spectrum disorder,ASD)是这类疾病的总称,较严重的状况称为自闭症或经典自闭症谱系障碍,其他的类型有阿斯伯格综合征(Asperger syndrome)、儿童期分裂障碍(childhood disintegrative disorder)和非特异的广泛性发育障碍(pervasive developmental disorder not otherwise specified,PDDNOS)等。虽然ASD的特征和严重程度各异,但在各种族和经济阶层中都会出现,并对任何年龄段人群都可能造成影响。
不容乐观的是自闭症的患病人数在逐年增加,据美国疾病控制与预防中心统计,截止到2010年,美国8岁的儿童中每68人中就有一人患有ASD,并且男性患病比例约为1/42,是女性的4~5倍。而2013年的报告显示,在6~17岁的孩子中每50个孩子中就有1个患有自闭症,增长趋势十分明显。来自不同国家的统计表明,自闭症在总人口的患病比例可达2%甚至更高。在美国,每个自闭症儿童一生的护理费用超过320万美元,全国每年的花费超过350亿美元。然而,目前我国还缺乏官方的统计报告,据世卫组织统计,中国大陆的自闭症儿童数量约为60~180万人,有学者则认为实际数量可能达到260~800万人。自闭症已经成为儿童精神类致残的重要疾病,随着发病率的升高,正在并将持续给家庭和社会带来巨大的社会和经济负担。
自闭症由环境因素,生物和遗传因素等共同作用引起,目前的治疗措施主要包括行为干预和药物干预。然而,到目前为止,人们对自闭症的致病机制尚未完全阐明,也还没有切实有效的针对核心症状的治疗方法。本文将对近年来发现的致病因素和自闭症的治疗方法进行综述,着重从生物学相关的致病因素和治疗方法进行综述,特别介绍了最具前景的肠道微生物相关疗法,以期为广大科研人员、医疗工作者和相关人员提供参考。
1自闭症的致病因素
1.1遗传因素
对自闭症患者的双生子和家庭成员的研究表明,一些患者存在明显的遗传易感性。同卵双生子之一患有自闭症,另一个的患病几率可达60%,甚至90%;而异卵双生子则只有5%的患病几率,结合自闭症的发病率,有研究推测自闭症及类似行为特征的遗传性达90%。除此之外,直系亲属患病率也受遗传因素影响,自闭症患儿的兄弟姐妹患病风险会明显增加;家庭中有一个孩子患有自闭症,那再生一个孩子患病几率可达5%~6%。研究者还发现,自闭症孩子的家庭成员出现较多的社交技能或重复性行为异常,以及某些情感障碍类精神疾患,如躁郁症等。还有理论认为两个具有重复、刻板、注重秩序和规则等超系统性(hyper-systemising)行为比较明显的人结婚后更容易生出自闭症的孩子。
自闭症的遗传学因素主要集中在基因突变和染色体异常,包括点突变、基因拷贝数变异、连锁区域和microRNAs等。具有特定遗传或染色体特征的人更容易患自闭症,如脆性X染色体综合征或结节性硬化症(tuberous sclerosis)。虽然,基因是自闭症的一个风险因素,然而,到目前为止尚未确定自闭症基因,仅报道了一些潜在的易感或致病基因,如CNTNAP2(contactin associated protein like-2)基因、突触蛋白基因SHANKs (SH3 and multiple ankyrin repeatdomains)和NLGN4X (neuroligin 4,X-linked)基因等。另外,结节性硬化症基因可能与自闭症相关,据估计,大约在1%~4%的自闭症患者中能够检测到该基因异常。在某些自闭症儿童体内影响大脑发育的拓扑异构酶相关基因(如TOP1)发生了突变导致表达量降低。自闭症患者表现了高度的遗传异质性,仍不清楚这些基因是单独或组合影响自闭症的发生,如NRXN1(neurexin-1)基因是维持脊椎动物神经系统功能的细胞黏附分子和受体的一组蛋白家族基因,可能参与了自闭症和精神分裂症的形成,然而,大规模调查并没有发现自闭症儿童体内相应的编码序列的异常,并且这个基因单独并不会导致自闭症,必须与其他因子一起才可能引起自闭症。据估计,大约3~12个基因协同作用才可能导致自闭症,并且这些可疑的基因多位于第2号、5号、7号和16号染色体上。科研人员已经构建某些神经生物学相关的基因异常的自闭症动物模型来进一步研究。
尽管研究认为自闭症是一种复杂的多基因控制的遗传性疾病,然而并没有发现确切的自闭症致病基因,仍不清楚它们之间的联系机制。事实上,遗传学因素大约能够解释10%~30%的自闭症成因,它的发病率逐年迅速升高明显偏离哈迪-温伯格平衡(Hardy-Weinberg Equilibrium),提示自闭症是遗传和外部环境相互作用引起的疾病。而环境可能更是值得我们关注的因素。
1.2环境因素
(1) 生物异源物质/重金属 杀虫剂、农药、添加剂和防腐剂等正常人体不存在的生物异源物质(xenobiotics)进入体内会对人体产生伤害。某些重金属,如砷、铅、汞、镉、锑和锰等会对人体神经系统产生毒害。有研究发现,重金属和生物异源物质会引起硫代谢异常,氧化还原水平以及甲基化都会受到影响。
起初,人们注意到自闭症儿童通常在发病前进行过疫苗注射,并怀疑其中的防腐剂-硫柳汞(thimerosal)才是导致自闭症的罪魁祸首。但后续研究否定了这一发现。此外,疫苗中的抗体刺激蛋白和多糖与自闭症并不相关。虽然研究结果不一,但为了谨慎起见,世界卫生组织已经不再鼓励在疫苗中使用硫柳汞作为防腐剂。
值得注意的是汞对人体健康的影响并不简单。在正常情况下,人体能够将汞代谢为乙基汞(ethylmercury),大约18 d内就被排出体外。然而,在体外,某些肠道微生物能够将汞甲基化或去甲基化,甲基化的汞具有神经毒性,可破坏神经系统,引起脑萎缩。历史上著名的环境污染事件“日本水俣事件”就是由于环境中的微生物将污水中的汞转化为甲基汞而引起的中毒事件。此外,用抗生素清除大鼠(Rattus norvegicus)肠道中的微生物后,会导致组织中汞的含量增加,并且甲基汞的比例也明显增加。因此,在研究物质的毒性时,需考虑微生物的影响,某些肠道微生物可能将本身无毒的物质转化为有毒的物质,对含汞疫苗的安全评价应考虑特定肠道微生物的代谢。
除汞外,另一种环境中常见的重金属-铅在自闭症患儿体内的含量也显著高于对照组。一项对5~16岁的55位自闭症儿童和44位对照的研究发现,重金属在自闭症患儿血液和尿液中含量更高,其中自闭症组血液中铅的含量高于对照组41%,尿液中的铅、铊、锡和钨含量分别比对照组高74%、77%、115%和44%,而血液中钙含量却比对照组低19%,并且,自闭症的严重程度与体内的重金属含量密切相关。
某些生物异源物质也可能导致自闭症。有研究通过使用致畸剂,如常用的抗痉挛(anticonvulsant)药丙戊酸钠(sodium valproate)处理怀孕的母鼠,丙戊酸钠在母鼠体内生成的丙戊酸(valproic acid,VPA)会导致后代出现类似自闭症症状的发育和行为异常,并持续到成年。目前,尚未有具体的影响机制报道,推测可能是丙戊酸通过影响叶酸代谢、组蛋白脱乙酰作用、氧化应激、突触可塑性和神经细胞凋亡导致神经系统发育异常。
(2) 怀孕 自闭症的发病时间通常是三岁以内,关键时期是出生之前、期间或出生后不久,这段时间正是幼儿生长发育的关键时期,极易受到外界环境的影响。研究发现,怀孕期间的多种影响因素都有可能影响孩子的神经系统发育,如怀孕期子宫感染和孕期并发症、接触化学物质、环境污染、围产期和产后健康状况等都将增高幼儿患病风险。
动物研究发现,产前应激会使母鼠脑中五羟色胺(血清素serotonin或5-hydroxytryptamine,5-HT)的含量显著升高,而它的代谢产物五羟吲哚乙酸会在后代中积累,导致后代婴儿期出现行为缺陷。在怀孕和围产期感染病毒也可导致后代患自闭症和精神分裂症的风险增加。有研究发现,给怀孕母鼠注射人流感病毒后,其产生的后代会出现缺乏探究行为和交流行为等类似自闭症的异常行为。可能产前应激在人体内也会有类似的影响。
有研究报道,父母生育孩子时的年龄越大孩子患自闭症的风险越高,并且祖父母晚育也会增加第三代患自闭症的风险。最近的一项研究表明,自闭症儿童母亲的年龄显著高于对照组,且约有50%的患者曾经有过产前并发症。在怀孕期间服用药物可能增加自闭症风险,如孕期服用处方药丙戊酸和萨力多胺等。此外,母亲孕期接触可卡因和酒精,病毒感染以及甲状腺功能减退等都可能提高孩子患自闭症的风险。孕妇生活的环境会影响孩子,环境污染会增加自闭症的发生率,研究发现,怀孕期间以及在孩子出生后的第一年暴露于交通空气污染中高浓度的二氧化氮,PM2.5和PM10会增加孩子患自闭症的风险。因此,对自闭症的诊断和预防可能并不需要等到孩子长大,而是在孩子出生时,孕期乃至在母亲怀孕之前就应该进行后代自闭症风险评估和干预。
(3) 肠脑 肠道里的神经细胞在细胞类型、神经递质及感受器方面都与大脑极其相似,与大脑的神经细胞数量相当,比脊髓里的还多,常见的5-HT、多巴胺(dopamin,DA)、谷氨酸、去甲肾上腺素、一氧化氮、阿片肽、P 物质、促胃激素、促胰激素等神经递质和激素在大脑和肠神经系统都有广泛分布,因此,肠道也被称为人的“第二脑”或“肠脑”。肠脑与头脑之间双向互通,它们之间通过脑-肠轴(brain-gut-axis)进行联接。肠脑能够影响中枢神经系统,进而影响人的情感,认知和行为,并且肠道微生物可能在其中具有重要作用。自闭症可能也受脑-肠轴的影响。
肠道是人体最大的消化器官,负责营养物质的消化和吸收,小分子物质能够被肠道直接吸收,某些大分子物质需要通过特定的通道或受体才能被人体吸收。自闭症患者通常伴有肠道异常,当肠道出现炎症时,会引起肠道细胞肿胀,细胞间隙变大,引起肠漏(gut leakage),导致大分子物质能够穿透肠壁进入体内,此外,严重的肠道问题可能伴随肠道的破损和溃疡,大分子物质就更容易进入肠道。
研究发现,2006—2010年,美国3~17岁的自闭症儿童患有腹泻或结肠炎的比例是正常人的7倍。最近的一项研究发现,61%的自闭症儿童同时伴有至少一种胃肠道症状,并且所有伴有消化道症状的儿童情感问题都比较严重。此外,不同群体自闭症患者同时伴随胃肠道症状的比例不同,大约为9%~91%,这种巨大差异可能是由于调查过程中,自闭症患者语言和沟通障碍造成的。自闭症的胃肠道症状主要包括:淋巴结节性增生、小肠结肠炎、胃炎、食管炎、肠道通透性增加、双糖酶活性不足、淋巴细胞种群密度较高、异常的细胞因子和免疫球蛋白(IgG)等。有研究发现,患有自闭症的儿童中有1/4伴有腹泻,1/4伴有便秘,并且胃肠道炎症影响患者对营养物质的吸收,有36.7%的自闭症儿童肠道通透性增加,而进行无酪蛋白/谷蛋白饮食控制的患者相比没有进行饮食控制的患者和对照,他们肠漏症状显著减轻。
(4) 肠道微生物 近年来的研究发现,人体携带有1~2 kg的微生物,这些微生物总数量达人体自身细胞数量的10~100倍,编码的基因数量是人体自身的300多倍,被称为人体的“第二基因组”或“被遗忘的器官”。肠道微生物能够帮助人体消化和吸收营养物质,通过分泌各种酶类,合成某些维生素和生物活性物质影响人体代谢、控制体重、塑造人体免疫系统以及帮助抵御病原微生物的侵入,并且血液中大约70%的物质来自于肠道,其中36%的小分子物质是由肠道微生物产生。肠道微生物的平衡对人体健康至关重要,这种平衡一旦被打破将可能导致多种疾病。
最近的研究显示,粪便中有超过90%的DNA序列来自肠道微生物,这些微生物主要属于两个门:拟杆菌门(Bacteriodetes)和厚壁菌门(Firmicutes),并且可以大致聚类为以拟杆菌属(Bacteroides)、普氏菌属(Prevotella)和瘤胃球菌属(Ruminococcus)3个属的微生物为主的类型,称为肠型(enterotypes)。肠型是稳定的,几乎不受饮食等因素的影响,可用于区分个体的肠道微生物特征,研究发现,自闭症儿童具有其独特的肠型,他们大多为拟杆菌属和瘤胃球菌属肠型,而缺少普氏菌属肠型。
肠道微生物可通过血液系统,内分泌系统和神经系统影响大脑和行为,它们之间相互影响构成了微生物-肠道-大脑轴(microbiome-gut-brain axis,也称菌-肠-脑轴)。肠道微生物不仅影响人体的生理健康,并可能通过神经化学物质的变化,影响人的心理和行为。肠道微生物还能够影响记忆的形成,因而推论,自闭症也受菌-肠-脑轴的影响。有研究发现,自闭症样小鼠(Mus musculus)肠道通透性增大,肠道中微生物的代谢产物能够进入血液循环系统并且可以改变宿主特定的行为。
个体的发育不仅由父母垂直传递的基因决定,还受水平传递的、定植于肠道的微生物影响。个体肠道菌群有自己的生长发育规律,婴儿出生后微生物逐渐定植,一岁左右肠道微生物趋于稳定,3岁左右与成人类似或一致。早期研究认为婴儿在母体子宫中是完全无菌的,随着测序技术的发展,在胎盘中也可检测到微生物,它们有可能很早就定植在胎儿肠道中。此外,出生方式不同会导致婴儿体内定植的微生物群不同,剖腹产和顺产的婴儿其肠道菌群差异显著。不同出生方式使婴儿接触微生物的时机和部位不同,导致肠道中微生物定植的差异。喂养方式也会导致微生物的差异,出生后采用母乳喂养与吃配方奶的婴儿的肠道微生物构成也存在显著差异。母亲直接哺乳可通过乳头和乳汁向婴儿传递有益细菌,而吃配方奶或使用奶瓶奶嘴则使婴儿无法从母亲体内获取特定的有益微生物,因此,微生物的传递被阻碍可能导致健康和大脑发育异常等一系列问题。
自闭症儿童的消化道症状可由特定的肠道微生物引起,并且肠道早期定植的微生物出现异常可能会干扰大脑发育,引起或促进后代出现自闭症症状。值得注意的是,自闭症儿童在一岁以前开始出现症状,大多数发病都是在3岁以内,这与婴儿肠道菌群的发育过程的时间节点重叠,推测婴儿的大脑发育需要伴随肠道微生物的正常定植而完成。所以,自闭症可能为婴儿早期肠道微生物的发育异常导致。目前,已经发现了一些疑似与自闭症密切相关的肠道微生物或菌群组成紊乱,一些在正常人体内出现的细菌缺失,或者出现了正常人体内没有的菌群,或者各种菌群的比例发生了明显变化,有益菌减少,有害菌增加。
梭菌属(Clostridium)细菌 最初,人们怀疑梭菌属细菌可能跟自闭症关系密切,如破伤风梭菌(Clostridium tetani)、产气荚膜梭菌(Clostridium perfringens)以及梭状芽孢杆菌(Clostridium bolteaenovo sp.)等。梭菌是肠道中的“坏菌”,可产生酚类、对甲酚或某些吲哚衍生物等毒性物质或前体物质。研究发现,在晚发型自闭症(late-onset/regressive autism)患者中,肠道菌群明显紊乱,由梭菌产生的破伤风毒素(tetanus antitoxin)的浓度异常高,肠道中梭菌和瘤胃球菌属细菌数量明显高于对照组,自闭症儿童粪便中25种不同的梭菌,有9种梭菌在对照组中不存在,而对照组中有3种梭菌在自闭症组中也没有发现,且自闭症儿童的消化道上游和下游的微生物发生了明显改变。然而,这一研究主要基于细菌培养,也不能排除饮食干预的影响。另有研究发现,自闭症患者体内的梭状芽孢杆菌(Clostridium bolteae)是正常对照组的46倍,梭状芽孢杆菌(Clostridium clusters)Ⅰ和Ⅺ则分别是正常对照组的9倍和3.5倍。自闭症儿童肠道中的溶组织梭菌(Clostridium histolyticum)比例也明显偏高,溶组织梭菌产生的毒素可能导致肠道异常和功能紊乱,并且还可能进入血液系统,再透过血脑屏障影响大脑发育。
脱硫弧菌属(Desulfovibrio)和萨特菌属(Sutterella)细菌。除梭菌外,最近也发现了其他可能与自闭症相关的细菌。如脱硫弧菌属(Desulfovibrio)和萨特菌属(Sutterella)。在自闭症儿童中,大约50%的患者中存在脱硫弧菌,其兄弟姐妹中有一部分存在,而正常人中几乎没有。这种硫酸盐还原菌属于革兰氏阴性厌氧弧菌,能够引起硫代谢异常,通过检测自闭症患者的血液和尿液,确实发现自闭症儿童血液中硫含量较低,而尿液中硫含量较高,推测脱硫弧菌可能通过影响儿童体内的硫代谢过程引起自闭症。
美国哥伦比亚大学的研究人员发现,有超过1/2的伴有胃肠功能障碍的自闭症儿童肠道中存在另一种肠道微生物—萨特菌,而正常人中没有发现。萨特菌属于产碱菌科(Alcaligenaceae)可抵抗胆碱,约占肠道中全部细菌的1%~7%。然而,目前还不清楚其影响机制。
酵母菌(Yeast) 白色念球菌(Candida albicans)属于酵母菌,是引起肠炎和阴道炎的一种致病真菌。有研究认为自闭症与真菌的过度增殖有关,制霉菌素(nystatin)、氟康唑(fluconazole)和酮康唑(ketoconazole)等抗真菌素类药物或酵母抑制剂(yeast inhibitor)可改善自闭症症状。白色念球菌能够产生一种类似γ-氨基丁酸(γ-aminobutyric acid,GABA)的β-丙氨酸,可越过血脑屏障与GABA进行竞争,干扰GABA的正常功能。有研究发现,自闭症患者体内β-丙氨酸显著高于正常人,可能是由于自闭症患者肠道中的白色念球菌产生了大量β-丙氨酸,透过血脑屏障后与抑制性神经递质GABA进行拮抗,导致大脑加速产生GABA,最终导致自闭症患者在社会交往能力方面受到抑制。
其他肠道微生物 除了上述几种微生物在自闭症患者和正常人之间存在差异,最近的研究还发现自闭症患者肠道中的厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidetes)的比例比正常人低,而放线菌门和变形菌门在严重自闭症患者中明显增多,脱硫弧菌属和普通拟杆菌(Bacteroides vulgatus)的比例也都显著高于对照组。此外,粪杆菌属(Faecalibacterium)和瘤胃球菌属(Ruminococcus)在PDD-NOS患儿和健康对照儿童粪便样品中含量更多,而喜热菌属(Caloramator)、八叠球菌属(Sarcina)和梭状芽胞杆菌属在自闭症儿童粪便中最多;与健康对照相比,毛螺旋菌科(Lachnospiraceae)的组成与PDD-NOS患儿显著不同,特别是与自闭症儿童差异更大;除了惰性真杆菌(Eubacterium siraeum)外,真杆菌科(Eubacteriaceae)在自闭症儿童粪便中最少;拟杆菌属和一些Alistipes 和Akkermansia 菌在PDD-NOS和自闭症患儿粪便中最高;几乎所有确认的萨特菌科(Sutterellaceae)和肠杆菌科(Enterobacteriaceae)在自闭症儿童粪便中均为最多,而与健康对照相比,自闭症儿童粪便中双歧杆菌却明显减少。
另有研究发现,自闭症儿童粪便中除了萨特菌(Sutterella spp.)比对照组明显增多,伴随有功能性胃肠疾病的自闭症儿童粪便中毛圈瘤胃球菌(Ruminococcus torques)相比无功能性胃肠疾病的自闭症儿童也明显增多。
通过比较3~16岁的自闭症儿童和正常儿童(每组20位)的肠道菌群、肠道症状和自闭症症状,发现自闭症儿童肠道菌群中普氏菌属(Prevotella)、粪球菌属(Coprococcus)和未分类的韦荣球菌科(Veillonellaceae)明显减少;自闭症儿童肠道菌群多样性与自闭症症状相关性更强;菌群整体的多样性和个体菌属丰度与自闭症相关症状相关,而与他们的饮食模式没有相关性。表明肠道菌群丰度与自闭症症状联系更紧密,肠道菌群丰度低或肠道菌群紊乱可能导致自闭症。
干预研究表明,通过调节或干预肠道微生物能够对自闭症症状有所改善。在人类中,严重的病毒感染会导致怀孕母亲生出患有自闭症的孩子,来自美国的研究人员通过模拟病毒感染引起母鼠出现免疫反应,出生的小鼠会出现自闭症样行为。通过这样的处理构建的自闭症模型小鼠同时出现胃肠道异常症状,主要为通透性增加,而这种症状同样存在于一些自闭症儿童中。研究人员用益生菌-脆弱拟杆菌(Bacteroides fragillis)来处理自闭症样小鼠,结果小鼠的肠道通透性得到明显改善,自闭症样行为也有所改善。不仅在动物实验中,在自闭症儿童体内也发现了类似的结果,在给予10名自闭症儿童和9名他们的兄弟姐妹以及10名对照益生菌之后,自闭症儿童体内拟杆菌门/厚壁菌门的比例,脱硫弧菌属和双歧杆菌属细菌的比例均得以恢复。这几项研究既发现自闭症患者肠道菌群的不同,又通过益生菌干预了肠道菌群,并改善了自闭症样行为,表明肠道菌群异常可能是引发自闭症重要原因。
肠道微生物对宿主的影响除了肠道微生物本身,还包括肠道微生物的代谢对宿主的影响,后续的研究除了需要检测肠道微生物的差异,还要检测肠道微生物的代谢物的变化,肠道的pH、氧化还原水平、氧气、氢气、短链脂肪酸和生物活性肽的含量等都会影响肠道微生物的分布和构成。尽管发现自闭症与肠道菌群有关,这些研究难以排除一些干扰因素,如种族、饮食、并发症和病人的信息反馈等。目前,尚不能确定肠道菌群是自闭症的发病原因还是结果,或者只是混淆因素,因此,肠道菌群的研究仍需时日。
(5) 饮食和营养 患有自闭症的儿童通常对味道、质地和气味等感官刺激极端敏感,并对吃的东西极其挑剔。据估计,有超过90%的自闭症儿童存在饮食问题。有一些父母反映他们患有自闭症的孩子只吃五六种食物,更喜欢富含脂肪、淀粉类食物、零食和加工食物,而厌恶大多数水果、蔬菜和蛋白质。然而,父母有限的时间、繁重的工作和巨大的心理和经济压力都有可能影响孩子的饮食习惯,目前,还不清楚自闭症儿童的饮食特点是否受到其照料和监管人的人为影响。
婴儿时期的饮食习惯会对其身体健康状况产生持续的、长期的影响。挑食的儿童纤维素类营养更缺乏,而缺乏纤维素会导致胃肠道功能紊乱,尤其是便秘。有限的食物种类必然导致营养不良,缺乏必需的营养和一些酶类,会进一步降低对食物的消化吸收能力,从而形成恶性循环。自闭症儿童与正常儿童相比,营养物质摄入水平要显著低很多,骨密度也比正常孩子低,自闭症患者摄入维生素B6,B12,维生素E,D和C;微量元素镁、铁、锌和钙以及叶酸等严重不足,明显低于推荐摄入量。自闭症儿童的这种饮食特点并不是在患病之后才出现的,往往从婴儿时期就开始并持续很长时间。
除了缺乏营养物质,食物中的某些成分也可能引起食物不耐受或过敏。自闭症患者的免疫球蛋白抗体,如IgG,IgE和IgA等水平普遍偏高。人们发现,通过减少或杜绝某些食物能够减轻自闭症的某些症状,严格限制食物中的酪蛋白和谷蛋白后自闭症患者症状明显改善。可能由于自闭症患者本身对这些食物成分不耐受或过敏,也有人认为这两种蛋白质在自闭症孩子体内会被分解成某些引起大脑异常的类神经递质,包括具有阿片活性的多肽或短的氨基酸聚合物外啡肽(exorphins),如谷啡肽(gluteomorphins)和β-酪啡肽(beta-casomorphins)。然而,目前对其具体的机制还不是很清楚。
食物在塑造和维持肠道微生物方面具有决定性作用。有研究发现,母乳中含有多种共生微生物,是婴儿体内常见的乳酸菌和双歧杆菌等有益微生物的绝佳来源。婴儿出生时,母乳提供婴儿发育所需的各种营养物质,以及一些保护性因子,而配方奶中缺乏这些物质,尤其是母乳中的共生微生物。此外,肠道菌群的紊乱会导致代谢异常,细菌产生的维生素B12、维生素H 和维生素K等会严重缺乏,也会导致明显的营养不良。
食品添加剂也可能增加儿童患自闭症的风险。人工色素、防腐剂等常用的食品添加剂对儿童的大脑发育有不利影响,食品中的色素或苯甲酸钠等能够使3岁和8~9岁的儿童出现多动症。一项来自美国的调查显示,从2005—2010年的5年间,在6~21岁的人群中,自闭症患者升高了91%,但这种升高跟汞的摄入没有关系,而与一种食品添加剂—果葡糖浆(high fructose corn syrup,HFCS)的消费密切相关,过多的果葡糖浆摄入会导致锌、钙、铜和磷等微量元素的摄入失衡。
(6) 代谢 自闭症患者的营养状况不仅取决于他们从食物中摄取的营养物质,还在于自身的代谢。自闭症患者的氧化应激水平升高,能量运输能力下降、硫酸盐化作用和解毒能力降低,血液中存在低水平的生物素、谷胱甘肽、红细胞活性腺苷甲硫氨酸、血尿苷、血三磷酸腺苷(adenosine triphosphate,ATP)、红细胞烟酰胺腺嘌呤二核苷酸(nicotinamide adeninedinucleotid,NADH)、红细胞烟酰胺腺嘌呤二核苷酸磷酸(nicotinamide adenine dinucleotide phosphate,NADPH)、血硫酸盐以及血色氨酸,还存在高水平的氧化应激生物标记物和血谷氨酸。只是到目前为止还没有找到明确的自闭症的生物标记物。
氨基酸代谢 色氨酸是参与神经发育和突触发生的5-HT、喹啉酸和犬尿酸的前体物质。喹啉酸是构成脱氢烟酰胺腺嘌呤二核苷酸(NAD+)的前体,而NAD+是线粒体中重要的能量载体,是NADH的前体。喹啉酸和犬尿酸可影响免疫系统的活性,色氨酸的代谢异常可能会影响这些物质的产生,进而影响大脑的发育,神经免疫活性和线粒体功能。研究发现,自闭症患者的色氨酸代谢明显减少,导致脑中NADH的产生减少,影响线粒体的能量代谢,神经细胞的发育,轴突的生长以及神经的可塑性。从食物中摄入的色氨酸约有99%是通过犬尿氨酸代谢途径(kynurenine pathway)进行再加工,作为5-HT和褪黑素的主要前体,色氨酸的代谢直接影响它们的含量。此外,很多父母反映自闭症患儿的排泄物有樟脑球的气味(mothball-like odor),这是粪便中吲哚(indole)或粪臭素(skatole,也称三甲基吲哚(3-methyl-indole))特有的气味。这些臭味物质是肠道中的细菌代谢色氨酸产生的,一旦食物中的色氨酸或酪氨酸进入大肠,就会在尿中检测到大量的吲哚苷(indican)和吲哚3乙酸。通过检测尿液中这些物质的含量能够间接反映自闭症患者体内氨基酸代谢水平,可用于自闭症的筛查和检测,但其检测准确性有待验证。
5-HT是重要的神经递质,可调节大脑发育,包括细胞分裂、神经元迁移、细胞分化以及突触发生。30%~40%的自闭症儿童全血的5-HT 水平明显升高。大脑发育过程需要大量5-HT来满足大脑发育,因此,儿童期5-HT的合成能力非常强,是成年人的2倍,到5岁逐渐降低到与成年人类似的水平,且女孩5-HT合成能力比男孩下降较早,而自闭症儿童的5-HT合成能力明显异常。自闭症儿童体内的5-HT明显增多,大量合成的5-HT如果不能被及时有效地代谢掉,反而会影响大脑的发育,会引起下丘脑室旁核中催产素的降低,并增加杏仁核中降血钙素相关基因多肽(calcitonin gene-related peptide,CGRP),从而影响到对自闭症儿童至关重要的社会互动行为。此外,自闭症患者大脑中的5-HT转运绑定能力低于对照组,而DA转运绑定能力高于对照组。5-HT的水平可直接影响自闭症的某些症状,如睡眠障碍和情感障碍,并且自闭症患者体内的褪黑素含量也低于对照组。
硫酸盐代谢 硫酸盐可由半胱氨酸代谢产生,在体内参与解毒,儿茶酚胺的失活和合成脑组织黏蛋白的硫酸盐化等多种代谢途径,还影响血液中的神经递质、类固醇、黏多糖、酚类、氨基酸和多肽等物质的含量。通常自闭症儿童血液中的硫酸盐含量较正常人低,尿液中硫酸盐、亚硫酸盐、硫代硫酸盐比正常人高,硫氰酸盐的含量则比正常人低。大量的硫酸盐随尿液排出体外,而没有进入血液系统供人体利用,可能是自闭症儿童血液中硫酸盐含量较正常人低的原因。
还原型谷胱甘肽(reduced glutathione,GSH)是含有巯基的三肽,其活性基团是半胱氨酸的巯基,具有抗氧化和解毒作用,可转化为氧化型谷胱甘肽(oxidized glutathione,GSSG)。GSH一旦缺乏,会减弱机体的抗氧化能力,损伤机体,多数自闭症儿童体内GSH的量偏低,而GSSG的比例偏高,GSH/GSSG则明显降低。有研究发现甲基代谢和叶酸代谢过程能够影响GSH/GSSG的比例,对稳定氧化还原状态至关重要,并且能够影响自由基的清除、体内氧化还原的平衡、维持蛋白质氧化还原状态、酶的活性、细胞膜的完整性、信号转导、解毒,以及细胞的分化和凋亡。
脂肪酸代谢 有研究发现自闭症患者血液中脂肪酸水平明显异常。一旦脂肪酸代谢出现异常,或摄入脂肪酸不足将会导致大脑发育异常,增加患自闭症的风险。脂肪酸代谢过程能够为机体提供大量能量,并且涉及多种脂肪酸的转变,其中,中、短链脂肪酸不需载体可直接进入线粒体进行能量代谢,而长链脂酰CoA需要肉毒碱转运才能进入线粒体参与能量代谢。
丙酸(propionic acid,PPA)是一种由肠道微生物代谢产生的短链脂肪酸(short chain fatty acid,SCFA),在日常生活中通常被用作食物防腐剂。有研究发现,给大鼠注射丙酸能引起类似自闭症的社会行为障碍,其他类型的短链脂肪酸,如乙酸也可引起类似的行为异常。此外,自闭症患者血清中肉毒碱(carnitine)和丙酮酸(pyruvic acid)的含量明显降低,而丙氨酸和氨的量明显升高。肉毒碱在能量代谢中发挥重要作用,线粒体的异常可能导致能量代谢异常,而丙氨酸和氨能够影响大脑的正常工作。通过磁共振波谱分析(magnetic resonance spectroscopy,MRS)发现,自闭症儿童体内的能量代谢异常,患儿血液中乳酸明显增加,而脑中的N-乙酰-天冬氨酸(N-acetyl-asparate,NAA)含量明显降低,表明自闭症儿童脑中出现神经代谢紊乱并且神经系统已经受到一定程度的损伤。此外,理论上认为在怀孕后期到出生后早期,孩子需要大量的不饱和脂肪酸来维持大脑的正常发育,然而,有研究发现自闭症患者血液中omega-3多不饱和脂肪酸,特别是二十二碳六烯酸(docosahexaenoic acid,DHA)的量明显升高,omega-3/6的比例也明显升高,但由于其选取的被试年龄多为12~18岁,并不能很好地说明自闭症发病早期的状况,其结果只能提示家长,要慎重考虑,是否给孩子补充不饱和脂肪酸。
氧化还原平衡 自闭症患者体内的氧化水平要高于正常人,而甲基化活动则明显比正常人少。自闭症的氧化还原甲基化假说(redox/methylation hypothesis)认为环境因素在遗传上敏感的个体更易引起氧化应激反应异常,导致异常的甲基化,引起神经系统发育延迟,注意力缺陷和神经网络同步能力受损等。除了自闭症孩子,患有自闭症孩子的父母本身就代谢异常,他们的甲基化能力和依赖GSH的抗氧化和解毒能力都出现了异常。
S-腺苷甲硫胺酸(S-adenosylmethionine,SAM)是甲基供体,脱去甲基后生成S-腺苷高半胱氨酸(S-adenosylho-mocysteine,SAH),SAM/SAH 的比例可以作为甲基化能力的指标,在自闭症患儿体内,SAM和SAM/SAH 都显著降低,SAM/SAH 的降低引起DNA,RNA,蛋白质和磷脂的低甲基化(hypomethylation),导致基因和蛋白表达下降,酶活性降低和膜磷脂含量减少,进而影响正常的细胞功能。SAH 继续代谢可生成同型半胱氨酸(homocysteine)和腺苷(adenosine),约有1/2的同型半胱氨酸会通过依赖叶酸的甲基化循环途径分解为胱硫醚和半胱氨酸,而GSH是通过蛋氨酸转硫基途径合成的,半胱氨酸是GSH合成的限制氨基酸,因此,GSH的合成需要足够的叶酸、蛋氨酸和SAM 提供的半胱氨酸。自闭症儿童体内的叶酸、蛋氨酸合成酶活性、GSH水平明显降低,而同型半胱氨酸和SAH明显升高,且男孩体内GSH 比女孩更低,同型半胱氨酸比女孩更高,这可能是男性患病率更高的一个原因。SAM 和GSH具有协同作用,它们之间相互影响决定了体内的氧化还原水平,而体内氧化还原失去平衡可能导致自闭症。氧化还原失衡会引起活性氧(reactiveoxygen species,ROS)的产生,ROS在体内积累会对DNA、RNA、蛋白质、脂质、碳水化合物等产生化学修饰和功能改变,从而导致细胞功能出现障碍,而ROS 能够被谷胱甘肽过氧化物酶及谷胱甘肽还原酶等GSH相关的酶清除。因此,改变自闭症患者体内的氧化还原状态可能有助于自闭症的恢复。
(7) 过敏和自体免疫 自闭症与免疫关系密切,约有60%的自闭症患者伴有一定程度的免疫异常症状,并有可能作为新的治疗靶点。研究发现自体免疫性疾病与自闭症有关,自闭症患者家庭成员中患有自体免疫性疾病的比例明显增多,约有46%的自闭症患儿家庭成员中有两名以上曾患有自体免疫性疾病,患病人数越多则儿童患自闭症的几率也越大,常见的自体免疫性疾病包括Ⅰ型糖尿病、甲状腺机能低下症、乳糜泻、风湿性关节炎、系统性红斑狼疮、多发性硬化症等。推测自闭症也是自体免疫性疾病的一种,其他如精神分裂症、抑郁症和强迫症等心理相关疾病也都与自体免疫相关,并且在自闭症患者体内已检测到自体免疫相关抗体,如神经轴突丝蛋白(neuron-axon filament protein)、胶质纤维酸性蛋白(glial fibrillary acidic protein)和髓鞘碱性蛋白(myelin basic protein)等物质的自体抗体,可能是自体抗体和细菌抗体相互作用引起的免疫反应导致自闭症。此外,一项大型研究对比了2431位自闭症患儿的母亲和653位未经选择的育龄妇女血液中脑反应性抗体的水平,发现自闭症患者母亲体内脑反应性抗体的水平可达对照组的4倍,且抗体多集中在与自闭症关系密切的额叶皮质、海马和小脑区,较高的脑反应性抗体表明自体免疫水平较高,可能自闭症儿童的母亲的自体免疫水平会影响孩子的自体免疫状态,进而引发自闭症。
自闭症可能还与免疫因子和精氨酸加压素(arginine vasopressin)等神经肽相关,自闭症患儿相比对照组血浆中细胞转化生长因子-β1(transforming growth factor beta 1,TGF- β1)和白介素-23(interleukin 23,IL-23)水平明显降低,并且TGF-β1,IL-23和白介素-17(IL-17,interleukin 17)的含量与自闭症的严重程度负相关,而热休克蛋白-70(heatshock protein 70,HSP-70)、细胞转化生长因子β2(transforming growth factor beta 2,TGF-2)、半胱天冬酶-7(caspase-7)以及干扰素-γ(interferon-γ,INF-γ)明显升高。最近的一项研究再次表明,自闭症患者血液中TGF-β1的量显著低于对照组,自闭症与TGF-β1的含量负相关。TGF-β1作为一种免疫抑制细胞因子是维持体内免疫内稳态的关键,能够诱导和激活T细胞,因此,TGF-β1在自闭症患者血液中的低含量显示体内免疫状态异常。
免疫球蛋白水平在自闭症患者体内也存在异常,如免疫球蛋白IgG4在自闭症患者体内显著高于对照组,而IgG4是一种类似于IgE的与过敏有关的抑制性单价抗体,在慢性应激过程中发挥免疫调节作用。虽然,在过去的10年里,发现了很多与自闭症相关的免疫异常,但还没有确切的生物标记物能够用于自闭症检测。
自闭症也有可能与“讲卫生”有关。“卫生假说(thehygiene hypothesis)”是建立在对农村和城市疾病分布差异的观察之上的普遍哮喘和过敏性疾病的病因理论,流行病学调查显示,相对于发展中国家,清洁环境条件较好的西方发达国家哮喘和过敏性疾病的发病率更高,提示过于清洁的环境使儿童远离微生物和寄生虫,人体缺少微生物和寄生虫的刺激会影响免疫系统的发育,导致过敏和哮喘,而微生物是其中重要的影响因素。值得注意的是自闭症与过敏和哮喘具有相近的发病趋势、性别偏好和城乡差异,并且都跟免疫系统密切相关,很可能是“太干净”导致的。其机理可能是自闭症儿童从小生活的环境过于干净,被微生物“接种”的机会变少,导致免疫系统刺激不足,发育受阻碍,引起大脑发育异常,进而导致行为错乱、发育迟缓,影响语言和社会交往,最终引发自闭症。
2自闭症的治疗方法
目前,还没有治疗自闭症核心障碍的有效方法。然而,医生、科研人员和患儿家长尝试了多种治疗方法,积累了很多经验。常见的治疗方法有行为干预法、特殊教育法、药物治疗法、生物医学干预法以及心理干预法等,其中,常用的是使用高度结构化的和密集的技巧性训练来帮助儿童发展社会和语言技能的行为干预法,如应用行为分析。此外,还有一些有争议的治疗或干预方法,如补充和替代疗法(complementary and alternative medicines)。其中生物相关疗法包括:抗生素、抗真菌、抗病毒药物,胃肠道药物,营养补充剂疗法,限制或特殊饮食疗法,分泌素疗法,螯合疗法,高压氧疗法,静脉注射免疫球蛋白疗法等,其他非生物相关疗法包括:听觉整合培训、针灸疗法、颅骨疗法、器械辅助沟通疗法、按摩和气功疗法、互动节拍器疗法、灵气疗法、自然疗法、经颅刺激疗法和瑜伽等。据统计,约有50%~70%的自闭症患者会采用生物相关疗法,但大多缺乏完整有效的安全性和有效性评估,仍需更多的系统性的研究和评估。随着对人体微生物和自闭症关系研究的发展,与之相对应的干预或治疗方法,如食物干预、益生菌以及粪菌移植等逐步显示出其独特的安全性和有效性,是具有广泛应用前景的生物干预方法。
2.1药物
目前,还没有针对自闭症的特效药。现用的药物并非针对自闭症的核心症状,而主要是一些抗精神病药物,用于治疗焦虑、抑郁或强迫性精神障碍等,用于改变5-HT和DA等神经生化系统,并且只是针对部分自闭症症状。其中,利培酮(risperidone)和阿立哌唑(aripiprazole)是唯一通过美国食品药品监督管理局(Food and Drug Administration,FDA)认证的仅可用于5~16岁儿童的自闭症药物,其他选择性5-HT再摄取抑制剂西酞普兰(citalopram)、艾司西酞普兰(escitalopram)和氟西汀(fluoxetine)等可以用于治疗自伤行为和重复行为等严重的行为问题。治疗癫痫症状的抗痉挛药物和治疗注意力缺陷障碍的药物可有效地帮助自闭症患者减少冲动和多动,抗过敏的药物赛庚啶(cyproheptadine)对自闭症症状也有所缓解。据估计,有47%的患儿使用这些药物。
1998年曾报道使用分泌素(secretin)来干预自闭症,并取得了一定的效果,但由于只有三个样本,随后的研究发现分泌素的效果并不显著,可能存在安慰剂效应,因此,并没有得以推广。但是,可能这种产生于肠道的激素将人们的关注点最终引向了肠道对大脑的影响,为自闭症的治疗带来了新的希望。
虽然,医生会给自闭症患者开药,但药物并不能对自闭症的核心缺陷,即社交和沟通障碍起实质治疗作用。这些药物的有效性也低于其他类疾病,且都具有一定的副作用,在儿童用药方面仍欠缺足够的临床经验,因此,有必要限制对自闭症患者做大规模和长期用药治疗。
2.2抗生素
在发现一些自闭症的肠道症状后,人们开始尝试使用抗生素治疗肠道症状,并对自闭症症状也有所帮助。一些自闭症病人口服两种广泛用于厌氧菌感染的万古霉素(vancomycin)和甲硝锉(metronidazole或flagyl)后都有一定的治疗效果。其中,万古霉素可能主要通过影响革兰氏阳性厌氧菌发挥作用,高浓度的万古霉素还会清除艰难梭菌和大部分革兰氏阴性厌氧菌。万古霉素用于自闭症治疗时其有效性是短期的,一旦停用后就会出现反复,并且在治疗的每个疗程,每次中断都会复发,可能肠道中的某些微生物导致了自闭症症状,如在万古霉素治疗后,肠道中的厌氧球菌(Anaerobic cocci)消失了。
口服万古霉素不能进入血液系统,几乎不被人体吸收,而主要通过影响肠道微生物发挥作用,停药之后出现反复可能是肠道微生物产生了孢子,当停止使用万古霉素时,孢子活化为细菌继续影响肠道和神经系统,可产生孢子的梭菌属最值得怀疑。
需要注意的是,虽然某些抗生素不能被人体吸收,但当肠道出现炎症、溃疡等异常时,它们也会进入血液。此外,万古霉素和庆大霉素(gentamycin)通常用于其他抗生素无效时的严重疾病,被认为是对抗耐药菌的最后一道防线,一旦错误使用很容易引起细菌耐药性。所以,应慎重选择此类抗生素应用于自闭症治疗。
2.3食物
对自闭症的常规治疗通常是基于行为疗法、饮食疗法与药物治疗的组合疗法。而饮食疗法相比其他疗法易于掌握,风险和副作用相对较小,能够与其他疗法同时使用,所以更易被采用。适当的饮食能够帮助患者减轻痛苦,改善心理和胃肠道症状。目前,已有多种饮食干预方法和理论,主要包括无麸质/无酪蛋白饮食(gluten-free/casein-free diet,GF/CF)、特殊碳水化合物饮食(the specific carbohydrate diet,SCD)、肠道和心理综合征饮食(gut and psychology syndromediet,GAPS)、低草酸饮食(low oxalate diet)、生酮饮食(ketogenic diet)和法因戈尔德饮食(the Feingold diet)等。某些饮食方式对自闭症有一定的改善作用,获得了一些患者家庭的认可,但其机制仍缺乏科学根据,相应的研究也较欠缺,因此,只选取其中部分饮食干预方法加以介绍。
(1) 无麸质/无酪蛋白饮食 自闭症儿童常伴有食物不耐受或过敏,需要去除食谱中可能引起食物不耐受和过敏的食物。人们发现减少或杜绝含有谷蛋白和酪蛋白的食物能够减轻自闭症症状。GF/CF饮食干预法就是从食物中去除面粉、小麦(Triticum aestivum)、大麦(Hordeum vulgare)、燕麦(Avena sativa)可能含有谷蛋白的食物,并且杜绝所有奶和奶制品,包括牛奶、酸奶、奶酪以及奶昔等可能含有酪蛋白的食物。有研究显示,有超过1/2的父母在严格限制孩子食物中的这两种蛋白质后自闭症症状明显改善,并且7~9岁的患者对食物干预的反应较为明显。一项来自丹麦的研究调查了GF/CF饮食对自闭症儿童的社会交往行为的影响,经过12个月的饮食干预后,采用自闭症诊断观察量表(autism diagnostic observation schedule scale,ADOS),Gillim自闭症评价量表(Gillim autism rating scale,GARS)和文兰适应行为量表(Vineland adaptivebehavior scales,VABS)以及注意缺陷多动障碍量表-Ⅳ(attentiondeficit hyperactivity disorder Ⅳ scale,ADHD-Ⅳ)进行评估,发现干预后ADOS,GARS和ADHD-Ⅳ的得分明显升高。此外,对10个孩子连续1年的GF/CF食物干预后发现,使用食物干预的患者发育水平要比对照组明显变好。
虽然,已有大量相关研究显示GF/CF 食物干预对自闭症症状具有较好的影响,但具体作用机制仍不是很清楚。阿片样物质过量理论(opioidexcess theory)认为儿童摄入谷蛋白和酪蛋白会对其行为和发育造成的不利影响,或者是由于自闭症儿童对食物过敏或本身患有腹腔疾病,在食物进入肠道时会引起胃肠道不适,可能儿童表现出的不适应行为正是对胃肠道不适的一种反应。
这一疗法在全球非常流行,但其作用机制仍不清楚,且并非对所有自闭症儿童有效,还可能引起营养不良等副作用,因此受到一些质疑。在严格的双盲试验条件下,对2~16岁的自闭症儿童连续12周的GF/CF饮食干预后,发现GF/CF饮食并没有对自闭症症状显示出统计学上明显的改善,虽然有部分患儿的父母表示有改善作用。也有综述文章系统地比较了多个相关研究,表明目前的研究还不能充分证明这种饮食方式可以治愈自闭症。
(2) 特殊碳水化合物饮食 Gottschall于2004年首次介绍和描述了SCD疗法,其目的是缓解患者的吸收障碍症状并防止致病性肠道微生物的增长。此疗法比GF/CF饮食要求更严格,不仅完全无麸质,也无淀粉。研究者认为某些肠道微生物(肠道病原体)引起了胃肠道异常,并产生一些神经毒性物质影响自闭症儿童的大脑,而这些有害肠道病原体的生存需依赖难以消化的碳水化合物,因此,减少这种碳水化合物能够断绝这些有害肠道病原体的食物,“饿死”它们,从而抑制这些有害肠道病原体产生神经毒性物质伤害大脑。
自闭症患者肠道微生物发生紊乱时,肠道微生物不能分解那些未消化的淀粉和多糖等大分子物质,这些物质进入大肠内可能被有害菌加以利用生成毒性物质。SCD疗法严格限制了所有的淀粉和多糖类,绝大部分的酵母菌以及其他有害肠道病原体得以抑制,进而保护肠道微生态系统,减少肠道感染,恢复肠道健康。同时也建议摄入单糖、酸奶、酸乳酪或益生菌等,促进肠道中有益微生物的生长,有助于消化功能的恢复,改善行为、感知和语言发展。然而,这一疗法相关的科学报道较少,仍缺乏有效性和安全性评价。
(3) 肠道和心理综合征饮食 GAPS疗法是由Natasha Campbell McBride 博士发明,并且她曾用这种疗法治疗自己患自闭症的儿子。GAPS饮食是在SCD 饮食的基础上制定的饮食和康复法,用于改善多种消化系统异常和相应的心理问题。其食物构成中包括了主要的SCD成分,康复训练和营养指导,此外,GAPS疗法还特别推荐发酵食物和家庭自制肉汤,并给出了生活方式和排毒建议。
GAPS疗法与SCD疗法依据的理论不尽相同,GAPS更强调促进肠道菌群的平衡,而SCD饮食则注重控制病原微生物。因此,在食物类型上两者之间有所差别,如GAPS饮食中包括了在SCD饮食中不被允许的淀粉和糖等成分,GAPS的食物清单中还包括鱼肝油、必需脂肪酸、益生菌、维生素和微量元素等,并特别强调了营养补充剂的作用。目前,对这一疗法还缺乏科学验证,也欠缺有效性和安全性评价。
(4) 营养补充剂 褪黑素(melatonin)是一种动物松果体产生的胺类激素,由5-HT衍生而来。目前作为具有保健功能的膳食补充剂,具有促进睡眠、调节时差、抗衰老等作用。有50%~80%的自闭症患者伴随有睡眠障碍,并且褪黑素的水平也较正常人低。有研究将这种激素用于自闭症患者,发现他们的睡眠状况得到改善。但褪黑素有潜在的副作用,有可能引起癫痫发作。
肌肽(carnosine)是一种二肽氨基酸,具有抗氧化特性。它可能会影响GABA受体,具有保护神经的作用。双盲和安慰剂对照试验发现,给自闭症患者服用左旋肌肽8周后,能明显改善其语言能力,并且自闭症症状有所减轻。
维生素B6/Mg 联合使用能减轻自闭症症状。早期研究发现,给自闭症患者服用维生素B6和镁之后,44个严重自闭症患者中有15个症状得到改善,警觉性有所提高,并且爆发、消极、自残、刻板行为明显减少。然而,单独使用维生素B6或镁的改善作用并不明显,持续两周给予自闭症患者30 mg/kg维生素B6和10~15 mg/kg的镁,与单独使用镁或维生素B6相比,同时给予时自闭症症状改善明显。
甲基化维生素B12作为重要的辅因子参与甲硫氨酸的生成,能为转甲基和转硫基提供必需的甲基供体。半胱氨酸和谷胱甘肽具有抗氧化作用,一旦缺乏,将会导致机体的抗氧化能力减弱,造成机体的损伤。大多数自闭症儿童体内GSH的量偏低,而GSH/GSSH 明显升高。注射甲基维生素B12能够明显改善自闭症患者的社会交往行为、语言能力和其他行为问题。当给自闭症儿童使用甲基维生素B12持续一个月后,血浆中GSH的量明显升高,遗憾的是研究中缺乏对改善行为方面的评价。
微量营养物质(micronutrients)主要包括各种微量元素和其他微量营养物质。由于自闭症儿童常出现饮食异常,并且常伴有肠道问题,导致他们对食物的消化和吸收存在异常。大部分自闭症儿童存在营养不良,多种维生素和微量元素在自闭症儿童中普遍缺乏,其缺乏的程度与自闭症严重程度相关。给自闭症患儿补充维生素和微量元素,患儿睡眠情况和肠道症状明显好转,141位自闭症患者口服维生素和微量元素3个月后,他们的营养状况和代谢水平得到明显改善,甲基水平、谷胱甘肽、氧化水平、硫酸盐化水平、ATP、NADH和NADPH等都明显升高,并且多动和发脾气等行为与安慰剂组相比也明显减少。另一项研究发现,补充维生素和微量元素有助于提高自闭症儿童的营养和代谢水平,增加体内甲基化、谷胱甘肽氧化应激、硫酸盐化作用并提高ATP、NADH和NADPH的水平。此外,临床研究还发现服用维生素和微量元素复合物3~6个月后,自闭症患者在异常行为检查表(aberrant behavior checklist,ABC),临床整体印象(clinical global impression,CGI)以及自我伤害方面都获得很好的改善。
Omega-3不饱和脂肪酸对大脑发育至关重要,是组成神经膜鞘的重要物质,也是在细胞交流和免疫调节中的必不可少的类花生酸的底物。Omega-3不饱和脂肪酸主要包括二十碳五烯酸(eicosapentaenoicacid,EPA)和DHA。自闭症患者体内缺乏Omega-3不饱和脂肪酸,给自闭症患者服用EPA和DHA 6周后,与安慰剂组相比,在刻板、多动和不当言论等方面表现良好,干预12周后,多动行为明显减少,但在异常行为方面没有显著差异。
此外,在孕前和孕早期补充叶酸能够降低患自闭症的风险。其他一些营养补充剂,如N-乙酰半胱氨酸(N-acetylcysteine,NAC)、左旋肌肽(L-carnosine)、抗坏血酸(ascorbic acid,维生素C)等都有报道对自闭症症状有改善。其他有助于大脑发育的营养物质,如谷氨酸盐(glutamine)、低聚糖(prebiotic oligosaccharides)以及L-精氨酸(L-arginine)等也可改善自闭症症状。
2.4益生菌
胃肠道症状和自闭症之间存在关联,但它们之间的关系还不是很明确,因果关系仍不清楚。可能某些未知因素或病原菌引起了胃肠道症状和自闭症,或者两者之间相互影响,相互促进。已有研究证明,改善肠道菌群健康状况能够改善自闭症症状,自闭症儿童服用一些益生菌或吃富含益生元的发酵食物,同时,限制或避免能够影响肠道微生物的抗生素,含酒精或加工食品等,自闭症症状,特别是便秘、腹泻、炎性肠炎或肠易激综合征等肠道症状均得到了明显改善,推测可能微生物-肠-脑共同参与了自闭症的发病。近两年来,越来越多的研究表明,肠道微生物能够影响大脑发育、心理和行为。因此,通过改变肠道微生物可影响宿主的心理和行为,从而为自闭症的治疗带来新的希望。
益生菌是直接影响肠道微生物组成的活性微生物,相比食物干预,干预目标更明确,干预作用更直接和有效。富含益生菌和益生元的食物可提供大量有益细菌和促进有益菌生长的物质,通过发酵食品或额外补充益生菌可以明显改善肠道微生物和多种消化问题,然而,患有自闭症的儿童经常在食物选择方面存在困难,他们选择有限的食物种类,难以获得足够多的益生菌和益生元。因此,在自闭症人群中,通过强制和短时补充大量活性益生菌的方式可能比食物干预更有效。
一项研究给33名自闭症患者服用含有5种益生菌的胶囊和一种来自乳酸菌细胞裂解物的免疫激活剂21天后,88%的患者自闭症所有症状都有明显改善,包括语言沟通、社会交往、感觉和认知意识以及身体健康和行为等方面,48%的患者腹泻症状明显减少,52%便秘症状明显好转。遗憾的是这个研究中没有对被试设置纳入和排除标准和对照组。最近,一项来自斯洛伐克的研究表明,给自闭症儿童每天3次服用含有3种乳酸杆菌,2种双歧杆菌和1种链球菌的益生菌产品4个月后,自闭症儿童肠道中厚壁菌门显著减少,拟杆菌/厚壁菌的比例得以恢复,双歧杆菌和脱硫弧菌属显著减少,而乳酸杆菌属细菌的相对数量得以显著升高,推测自闭症是由梭菌属和脱硫弧菌属细菌的增加导致。
此外,益生菌能够显著降低自闭症患者体内真菌数量,明显改善自闭症症状。 L-阿拉伯糖醇(L-arabitol,LA)在哺乳动物体内产生,D-阿拉伯糖醇(D-arabitol,DA)作为真菌感染的检测标志只由真菌产生,自闭症患者尿液中DA含量显著高于正常人。在给22位自闭症孩子服用嗜酸乳杆菌后,尿液中DA的含量明显降低,并且DA/LA也显著降低,同时,眼神交流、社会交往和反馈行为等自闭症的典型行为也明显改善。
其他种类的益生菌也可能对自闭症患者有帮助。有研究人员用脆弱拟杆菌(Bacteroides fragillis)来处理自闭症样小鼠,小鼠的肠道通透性和自闭症样行为都得到明显改善。给20位3~16岁的伴有便秘的自闭症孩子服用4周的短双歧杆菌(Bifidobacterium breve)后,便秘症状都得到了明显改善,排便频率增多、粪便硬度降低、粪尿失禁的频率降低,并且腹痛症状也减少了。
虽然,这些研究存在样本量少,缺乏对照和安慰剂实验等问题,但其干预效果较为明显,甚至有些对自闭症的核心症状有所改善,表现出明显的优势。益生菌用于改善自闭症症状潜力巨大,但现在还不清楚是益生菌直接影响了自闭症患者大脑中某些区域的功能,改善了自闭症症状,还是通过先改善肠道菌群健康状况,得到恢复的肠道菌群进而影响自闭症的症状,抑或同时都起作用。
无菌小鼠是研究肠道微生物作用的理想动物模型。最近的研究发现,无菌小鼠脑中海马区5-HT含量显著升高,并且在肠道菌群恢复后5-HT含量也恢复正常。无菌小鼠对压力反应更敏感,海马和杏仁核区域的神经内分泌水平异常,表现出焦虑水平降低(进入高架十字迷宫中的开臂端更多,时间更长)和空间记忆丧失等。无菌小鼠脑中单胺类神经递质也发生了变化,而这种改变更多的出现在雄性个体中,表明雄性个体比雌性个体在神经系统发育方面出现异常的发生率更高。在人类中,男孩比女孩发病率更高可能也是基于类似的机制。此外,无菌小鼠大脑中相应的基因表达也出现异常,如脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)显著上调,海马齿状回的5-HT受体5-ht1a子型以及杏仁核的N-甲基-D-天门冬氨酸(N-methyl- D-aspartic acid,NMDA)受体NR2B亚基(NMDA receptor 2B subunit)都明显下调。BDNF可维持大脑的正常发育,5-HT受体缺乏会引起焦虑样行为,而NMDA的NR2B受体亚基对杏仁核的发育和正常功能至关重要,与恐惧、情绪以及学习和记忆密切相关。
肠道菌群对正常的社交行为发育至关重要,无菌小鼠表现出明显的社交障碍,特别是雄性小鼠,出现社交回避和刻板行为,对同类兴趣降低,对陌生个体的探究行为减少,而一些重复的行为增加,但当恢复肠道微生物后,社交回避和重复行为得到了改善,而社会认知障碍并没有变化。自闭症儿童表现出类似的社交和沟通障碍以及重复的行为,并且男孩发病的比例远高于女孩,因此,自闭症可能正是由于肠道菌群的改变导致的。已有的研究发现,肠道微生物能够影响大脑,不仅包括自闭症,还包括焦虑、抑郁和精神分裂等。
2.5粪菌移植
粪菌移植(fecal microbiota transplantation,FMT)是将健康人粪便中的菌群移植到受体人的肠道中,帮助其恢复正常的胃肠道菌群,用于治疗胃肠道及其他类型的疾病。FMT在国外已有50余年的应用历史,而我国至少已经有1700年的应用历史,全球已有数千例患者接受FMT治疗。2013年5月,美国FDA将FMT作为研究性新药纳入监管。目前,FMT作为一种器官移植方式,不仅用于治疗人的胃肠道疾病,如难辨梭状芽胞杆菌感染、抗生素相关性腹泻、炎症性肠病、肠易激综合征、代谢综合征、自身免疫性肠病、肠道食物过敏等,还用于神经发育不良与神经退行性疾病,并且可能对帕金森病和儿童自闭症等精神疾病具有一定疗效。目前,还缺乏FMT治疗自闭症的相关研究。
3研究展望
自闭症并不是由单一因素引起的,受遗传和环境共同影响。环境污染、生物异源物质、母亲孕期的健康状况、肠道健康状况、饮食和营养等因素都可能引起自闭症。但越来越多的证据表明,肠道微生物与自闭症之间存在密切的联系,上述因素或多或少地都对肠道微生物产生影响,因此,可能肠道微生物是引发自闭症的关键因素。相应的,针对上述影响因素,出现了多种治疗方法,包括药物、食物以及一些营养补充剂等,其中益生菌是其中比较有前景的治疗方法。随着人们对肠道微生物和自闭症关系的研究深入,越来越多的针对肠道微生物的干预和治疗方法开始出现,然而,肠道微生物和自闭症之间的具体影响机制还未阐明,仍不清楚究竟是某些肠道微生物的异常还是整个肠道微生态系统的构成才是自闭症的诱因,仍需更多研究。
虽然,目前已经发现了一些可能跟自闭症相关的肠道微生物或菌群组成,但由于大多数肠道微生物不能通过体外培养,而潜在的能够导致自闭症的微生物可能正是不能体外培养的细菌,它们的数量也许非常少,也可能它们是黏附在肠黏膜上,在粪便中数量极少,还有可能它们主要分布在小肠中,在目前的技术条件下,还不能对它们进行完整的取样和分析。也可能自闭症是肠道微生物生态系统出现问题导致的,并不是其中一种或几种菌导致的。当然,不同类型的自闭症以及不同严重程度的自闭症可对应不同的肠道菌群,即使发现了某些特定的菌群,也要经过类似科赫法则的严格验证过程才能得出准确的结论。通常情况下,自闭症患儿肠道状况得以改善后,自闭症症状也会随着减轻。益生菌改善自闭症症状,可能并不是通过改变肠道健康状况影响儿童的自闭症症状,而是益生菌本身产生某些神经活性物质直接影响儿童神经系统进而改善自闭症症状。益生菌的种类众多,乳酸菌、双歧杆菌和酵母菌属中都有一些菌对人体有益,但绝非所有菌种都有相同的作用,各种益生菌的作用机制也会存在差异。只有了解益生菌进入体内的实际作用,清楚地知道自身体内肠道菌群的状况,才能对症选择有效的益生菌。至今还有很多问题需要解答,肠道微生物将成为自闭症的重点方向。
每个个体拥有不同的遗传背景、菌群组成和生活环境,因此,最理想的治疗方式是根据不同个体采取个性化的治疗和干预措施。虽然已经出现了多种治疗自闭症的方法,但相关的研究却相对滞后,需要进一步研究干预方法的机理,对有效性和安全性进行科学评估。虽然某些治疗方法只能缓解特定的症状,并不能对自闭症核心症状有所帮助,但即使这样,出于提高患者生存质量,减少患者和家人负担的目的,仍需要积极主动进行治疗,并且越早进行治疗和干预越好。自闭症的发病可能在胎儿时期,甚至母亲怀孕时已经开始了,应该做到及早预防,在怀孕期间或怀孕之前,尽早咨询相关医生或专家,同时特别注意母亲怀孕前和怀孕期间的营养状况和代谢情况。孩子出生之后,也应密切注意孩子异常的啼哭,手捂肚子、拱起背部等行为,注意观察孩子的粪便、腹泻、便秘、打嗝及放屁等胃肠道异常等与肠道微生物状态直接相关的状况,从而尽可能地及早发现和降低孩子患自闭症的风险。在自闭症发病率相对较低的国家,孩子往往有更多的机会接触大自然,泥土以及动物,这些方式都是让人获得共生微生物的机会,特别值得我们思考和借鉴。此外,可能自闭症的发病率正是伴随着食品工业的发展逐年升高,传统的手工制作的婴儿食品正在被大量的方便食品、加工食品以及人工合成添加剂取代,需要引起家长们的关注。♦
(摘自《中国科学:生命科学》2015年9期。)
·高被引论文摘要·
被引频次:83
福建省儿童孤独症流行病学调查
罗维武,林力,陈榕,等
摘要:目的:了解福建省儿童孤独症的患病及分布情况。方法:抽查福建省不同地区14岁以下儿童共10802人,采取ABC量表筛查、CCMD-2-R及DSM-Ⅲ-R确定诊断的方法。结果:确诊为儿童孤独症的共3名,时点患病率为0.28‰。结论:福建省儿童孤独症的患病率在国外报道患病率范围之内,应加强对儿童孤独症的研究。
关键词:儿童孤独症;患病率;流行病学
来源出版物:上海精神医学, 2000, 12(1): 3-5
被引频次:68
自闭症诊断与干预研究综述
尤娜,杨广学
摘要:本文概述了当前国内外有关自闭症和“自闭类”障碍的定义与诊断、病因和干预方案的研究,并简要分析了未来研究的重点和方向。
关键词:自闭症;“自闭类”障碍;诊断;干预方案
来源出版物:中国特殊教育, 2006, 7(73): 26-31
被引频次:65
孤独症患病率回顾
樊越波,揭晓锋,邹小兵
摘要:回顾历年来国内外孤独症患病率文献报道,患病率有增加的趋势,对于患病率增加的原因,认识的加深可能是主要原因,而发病率是否增加存在争议。
关键词:广泛性发育障碍;孤独症谱系障碍;孤独症;患病率
来源出版物:中国儿童保健杂志, 2008, 16(4): 439-440
被引频次:53
三种儿童孤独症行为评定量表临床应用比较
李建华,钟建民,蔡兰云,等
摘要:目的:儿童孤独症的诊断缺乏特异性的生物学指标,量表评定有重要的临床指导价值,目前有多种量表用于评定。该文对孤独症行为评定量表(ABC)、儿童期孤独症评定量表(CARS或卡氏量表)、克氏孤独症行为量表(CABS或克氏量表)进行比较,以期为临床应用提供借鉴。方法:对28例孤独症患儿和34例对照组儿童分别采用ABC、CARS和CABS进行评估和比较。结果:三种评估方法在病例组与对照组间的评定结果均有极显著差异(P<0.01);DSM Ⅳ儿童孤独症诊断标准判断结果与CARS评估结果的一致性最好(Kappa=1),与ABC也有较好一致性(Kappa=0.87),但与CABS的一致性稍差(Kappa=0.60)。应用受试者工作特性曲线(ROC)进行综合比较,ABC取31为筛查界线分最好,其特异性为0.97、敏感性为0.89、一致率为0.94、阳性预测值为0.96、阴性预测值为0.92,且更适合3岁以上儿童使用;CARS取30为诊断界线分最好,敏感性、特异性、一致性、阳性预测值与阴性预测值均为1.0,且与年龄无关;CABS取6为筛查界线分更为理想,其特异性为0.91,敏感性为0.82、一致率为0.87、阳性预测值为0.88、阴性预测值为0.86,且3岁以上儿童使用优于3岁以下。结论:ABC、CARS及CABS是辅助诊断孤独症的重要评估工具,相互间具有较好的一致性;但如果同,同时兼顾敏感性、特异性、一致性、阳性预测值及阴性预测值,CARS优于ABC,而ABC又优于CABS。
关键词:孤独症;评估研究;孤独症行为评定量表;儿童期
来源出版物:中国当代儿科杂志, 2005, 7(1): 59-62
被引频次:53
孤独症行为量表试测报告
杨晓玲,黄悦勤,贾美香,等
摘要:采用孤独症行为量表(Autism Behavior Checklist)对国内60名孤独症儿童,157名精神发育迟滞儿童及108名正常儿童的试测,发现当量表总分≥31分作为孤独症筛查界限分时其信度、效度均为1,检验符合要求;当总分≥62分时,对诊断与鉴别诊断有较好的阳性率。量表项目出现频率提示,原量表项目在我国可以保留使用。性别、年龄因素对量表影响不大。
关键词:孤独症;量表;效度;信度
来源出版物:中国心理卫生杂志, 1993, 7(6): 279-280
被引频次:50
自闭症谱系障碍的症状、诊断与干预
陈顺森,白学军,张日昇
摘要:自闭症谱系障碍(autism spectrum disorders,ASD)是一种广泛发展障碍,以社会交往障碍、言语和非言语交流缺陷、兴趣狭窄和行为刻板等为主要临床特征。对ASD的准确诊断是早期干预的关键,也对患者的康复及其家庭幸福产生积极作用。日渐增长的发病率促进了对早期识别、诊断评估、以事实为基础干预的重视。在探索药物治疗ASD的基础上,中国传统医学方法,尤其是“靳三针”治疗ASD获得越来越多的实证支持。可以根据Simpson等人(2005)提出的指标体系对各种干预和治疗方法的疗效进行评价。今后研究将从认知神经科学的视角,尤其是将眼动技术与ERP、fMRI相结合,探索ASD的核心症状表征以及各亚类的特异性。
关键词:自闭症谱系障碍;流行病学;诊断;康复
来源出版物:心理科学进展, 2011, 19(1): 60-72
被引频次:43
关于自闭症的临床、实验心理学的研究
徐光兴
摘要:最近,国际上的临床心理学、实验心理学对自闭症的诊断、分类、发生率以及教育与治疗等,从各个角度展示了许多新的研究结果。实验心理学的调查结果表明,自闭症儿童的注意力异常,对视、听、触等感觉反应处理样式,不同于弱智儿童和正常儿童。语言障碍是自闭症儿童发展障碍中的核心症候,这与自闭症在社会性和人际关系上存在障碍有着密切的关系。进入90年代以后,对自闭症“心的理论”的各种实验研究,引起各国研究者的注目和争论。这不仅为自闭症的科学研究,也为发展心理学及认知心理学,人类系统工程学提供了许多新的研究课题,并对我国今后的自闭症研究工作产生一定的启示意义。
关键词:自闭症;心的理论;感情认知障碍
来源出版物:心理科学, 2000, 23(1): 38-41
被引频次:41
关于儿童自闭症行为矫治法的几个理论问题
黄伟合
摘要:了解儿童自闭症行为矫治法有助于提高自闭症治疗的质量和效果。本文讨论了有关儿童自闭症行为矫治法的几个理论问题。作者还介绍分析了中外自闭症文献中记载的儿童自闭症行为矫治法的临床实验及其治疗效果。
关键词:儿童自闭症;行为矫治法;功能分析法;替代行为;前期干预
来源出版物:心理科学, 2003, 26(3): 475-478
被引频次:40
天津市2~6岁儿童孤独症调查
张欣,季成叶,李金水
摘要:目的:了解天津市儿童孤独症现患状况及可能的影响因素,为预防康复提供依据。方法:采用分层整群抽样,在天津市两区县抽取2~6岁7316名儿童为对象,筛查和诊断儿童孤独症。结果:天津市儿童孤独症现患率为1.1‰(8/7316);男∶女=7∶1;城、乡患病率为1.4‰和0.8‰。孤独症患儿全部为智力低下者。结论:应针对儿童孤独症的智力、精神和神经损伤及早采取康复措施。
关键词:孤独症;现患率;儿童;智力低下
来源出版物:中国生育健康杂志, 2005, 15(4): 206-208
被引频次:40
10例孤独症儿童心理推测能力的测试分析
焦青
摘要:目的:探讨孤独症儿童的心理推测能力。方法:本研究使用自编的测验故事为测量工具考察了学龄孤独症儿童的心理推测能力。结果:孤独症儿童能理解他人的生理性和社会性愿望,并能依据他人的愿望预测他人的行为;基本能理解他人的积极性和消极性情绪;但他们在理解他人的虚假信念时则表现出明显的困难,并且不能理解他人由虚假信念所导致的认知性情绪。结论:依据孤独症儿童在理解他人虚假信念上的表现,提示孤独症儿童在理解他人虚假信念的能力上只存在着量上的差异而非质上的差异。
关键词:孤独症;心理推测;愿望;情绪;信念
来源出版物:中国心理卫生杂志, 2001, 15(1): 60-62
被引频次:1309
Strong association of de novo copy number mutations with autism
Sebat, J; Lakshmi, B; Malhotra, D; et al.
Abstract: We tested the hypothesis that de novo copy number variation(CNV) is associated with autism spectrum disorders(ASDs). We performed comparative genomic hybridization(CGH) on the genomic DNA of patients and unaffected subjects to detect copy number variants not present in their respective parents. Candidate genomic regionswere validated by higher-resolution CGH, paternity testing, cytogenetics, fluorescence in situ hybridization, and microsatellite genotyping. Confirmed de novo CNVs were significantly associated with autism(P=0.0005). Such CNVs were identified in 12 out of 118(10%) of patients with sporadic autism, in 2 out of 77(3%) of patients with an affected first-degree relative, and in 2 out of 196(1%) of controls. Most de novo CNVs were smaller than microscopic resolution. Affected genomic regions were highly heterogeneous and included mutations of single genes. These findings establish de novo germline mutation as a more significant risk factor for ASD than previously recognized.
来源出版物:Science, 2007, 316(5823): 445-449
被引频次:1279
Autism as a strongly genetic disorder: Evidence from a british twin study
Bailey, A; Lecouteur, A; Gottesman, I; et al.
Abstract: Two previous epidemiological studies of autistic twins suggested that autism was predominantly genetically determined, although the findings with regard to a broader phenotype of cognitive, and possibly social, abnormalities were contradictory. Obstetric and perinatal hazards were also invoked as enviro- nmentally determined aetiological factors. The first British twin sample has been re-examined and a second total population sample of autistic twins recruited. In the combined sample 60% of monozygotic(MZ) pairs were concordant for autism versus no dizygotic(DZ) pairs; 92% of MZ pairs were concordant for a broader spectrum of related cognitive or social abnormalities versus 10% of DZ pairs. The findings indicate that autism is under a high degree of genetic control and suggest the involvement of multiple genetic loci. Obstetric hazards usually appear to be consequences of genetically influenced abnormal development, rather than independent aetiological factors. Few new cases had possible medical aetiologies, refuting claims that recognized disorders are common aetiological influences.
来源出版物:Psychological Medicine, 1995, 25(01): 63-77
被引频次:867
Structural variation of chromosomes in autism spectrum disorder
Marshall, CR; Noor, A; Vincent, JB; et al.
Abstract: Structural variation(copy number variation [CNV] including deletion and duplication, translocation, inversion) of chromosomes has been identified in some individuals with autism spectrum disorder(ASD), but the full etiologic role is unknown. We performed genome-wide assessment for structural abnormalities in 427 unrelated ASD cases via singlenucleotide polymorphism microarrays and karyotyping. With microarrays, we discovered 277 unbalanced CNVs in 44% of ASD families not present in 500 controls(and re-examined in another 1152 controls). Karyotyping detected additional balanced changes. Although most variants were inherited, we found a total of 27 cases with de novo alterations, and in three(11%) of these individuals, two or more new variants were observed. De novo CNVs were found in similar to 7% and similar to 2% of idiopathic families having one child, or two or more ASD siblings, respectively. We also detected 13 loci with recurrent/ overlapping CNV in unrelated cases, and at these sites, deletions and duplications affecting the same gene(s) in different individuals and sometimes in asymptomatic carriers were also found. Not with standing complexities, our results further implicate the SHANK3- NLGN4-NRXN1 postsynaptic density genes and also identify novel loci at DPP6-DPP10-PCDH9(synapse complex), ANKRD11, DPYD, PTCHD1, 15q24, among others, for a role in ASD susceptibility. Our most compelling result discovered CNV at 16p11.2(P = 0.002)(with characteristics of a genomic disorder) at similar to 1% frequency. Some of the ASD regions were also common to mental retardation loci. Structural variants were found in sufficiently high frequency influencing ASD to suggest that cytogenetic and microarray analyses be considered in routine clinical workup.
来源出版物:The American Journal of Human Genetics, 2008, 82(2): 477-488
被引频次:865
A progressive syndrome of autism, dementia, ataxia, and loss of purposeful hand use in girls: Rett’s syndrome: Report of 35 cases
Hagberg, B; Aicardi, J ; Dias, K; et al.
Abstract: Thirty-five patients, exclusively girls, from three countries had a uniform and striking progressive encephalopathy. After normal general and psychomotor development up to the age of 7 to 18 months, developmental stagnation occurred, followed by rapid deterioration of higher brain functions. Within one-and-a-half years this deterioration led to severe dementia, autism, loss of purposeful use of the hands, jerky truncal ataxia, and acquired microcephaly. The destructive stage was followed by apparent stability lasting through decades. Additional insidious neurologicalabnormalities supervened, mainly spastic parapareses, vasomotor disturbances of the lower limbs, and epilepsy. Prior extensive laboratory investigations have not revealed the cause. The condition is similar to a virtually overlooked syndrome described by Rett in the German literature. The exclusive involvement of females, correlated with findings in family data analyses, suggests a dominant mutation on one X chromosome that results in affected girls and nonviable male hemizygous conceptuses.
来源出版物:Annals of Neurology, 1983, 14(4): 471-479
被引频次:824
Mutations of the X-linked genes encoding neuroligins NLGN3 and NLGN4 are associated with autism
Jamain, S; Quach, H; Betancur, C; et al.
Abstract: Many studies have supported a genetic etiology for autism. Here we report Mutations in two X-linked genes encoding neuroligins NLGN3 and NLGN4 in siblings with autism-spectrum disorders. These mutations affect celladhesion molecules localized at the synapse and suggest that a defect of synaptogenesis may predispose to autism.
来源出版物:Nature Genetics, 2003, 34(1): 27-29
被引频次:786
Functional impact of global rare copy number variation inautism spectrum disorders
Pinto, Dalila; Pagnamenta, AT; Klei, L; et al.
Abstract: The autism spectrum disorders(ASDs) are a group of conditions characterized by impairments in reciprocal social interaction and communication, and the presence of restricted and repetitive behaviours. Individuals with an ASD vary greatly in cognitive development, which can range from above average to intellectual disability. Although ASDs are known to be highly heritable(similar to 90%), the underlying genetic determinants are still largely unknown. Here we analysed the genome-wide characteristics of rare(<1% frequency) copy number variation in ASD using dense genotyping arrays. When comparing 996 ASD individuals of European ancestry to 1287 matched controls, cases were found to carry a higher global burden of rare, genic copy number variants(CNVs)(1.19 fold, P=0.012), especially so for loci previously implicated in either ASD and/or intellectual disability(1.69 fold, P=3.4 × 10-4). Among the CNVs there were numerous de novo and inherited events, sometimes in combination in a given family, implicating many novel ASD genes such as SHANK2, SYNGAP1, DLGAP2 and the X-linked DDX53-PTCHD1 locus. We also discovered an enrichment of CNVs disrupting functional gene sets involved in cellular proliferation, projection and motility, and GTPase/Ras signalling. Our results reveal many new genetic and functional targets in ASD that may lead to final connected pathways.
来源出版物:Nature, 2010, 466(7304): 368-372
被引频次:780
Association between microdeletion and microduplication at 16p11.2 and autism
Weiss, LA; Shen, YP; Korn, JM; et al.
Abstract: Background: Autism spectrum disorder is a heritable developmental disorder in which chromosomal abnormalities are thought to play a role. Methods: As a first component of a genomewide association study of families from the Autism Genetic Resource Exchange(AGRE), we used two novel algorithms to search for recurrent copy-number variations in genotype data from 751 multiplex families with autism. Specific recurrent de novo events were further evaluated in clinical-testing data from Children's Hospital Boston and in a large population study in Iceland. Results: Among the AGRE families, we observed five instances of a de novo deletion of 593 kb on chromosome 16p11.2. Using comparative genomic hybridization, we observed the identical deletion in 5 of 512 children referred to Children's Hospital Boston for developmental delay, mental retardation, or suspected autism spectrum disorder, as well as in 3 of 299 persons with autism in an Icelandic population; the deletion was also carried by 2 of 18,834 unscreened Icelandic control subjects. The reciprocal duplication of this region occurred in 7 affected persons in AGRE families and 4 of the 512 children from Children's Hospital Boston. The duplication also appeared to be a high-penetrance risk factor. Conclusions: We have identified a novel, recurrent microdeletion and a reciprocal microduplication that carry substantial susceptibility to autism and appear to account for approximately 1% of cases. We did not identify other regions with similar aggregations of large de novo mutations.
来源出版物:New England Journal of Medicine, 2008, 358(7): 667-675
被引频次:779
Mapping autism risk loci using genetic linkage and chromosomal rearrangements
Szatmari, P; Paterson, AD; Zwaigenbaum, L; et al.
Abstract: Autism spectrum disorders(ASDs) are common,heritable neurodevelopmental conditions. The genetic architecture of ASDs is complex, requiring large samples to overcome hetero- geneity. Here we broaden coverage and sample size relative to other studies of ASDs by using Affymetrix 10K SNP arrays and 1168 families with at least two affected individuals, performing the largest linkage scan to date while also analyzing copy number variation in these families. Linkage and copy number variation analyses implicate chromosome 11p12-p13 and neurexins, respectively, among other candidate loci. Neurexins team with previously implicated neuroligins for glutamatergic synaptogenesis, highlighting glutamate-related genes as promising candidates for contributing to ASDs.
来源出版物:Nature Genetics, 2007, 39(3): 319-328
被引频次:719
Visual fixation patterns during viewing of naturalistic social situations as predictors of social competence in individuals with autism
Klin, A; Jones, W; Schultz, R; et al.
Abstract: Background: Manifestations of core social deficits in autism are more pronounced in everyday settings than in explicit experimental tasks. To bring experimental n Measures in line with clinical observation, we report a novel method of quantifying atypical strategies of social monitoring in a setting that simulates the demands of daily experience. Enhanced ecological validity, was intended to maximize between-group effect sizes and assess the predictive utility of experimental variables relative to outcome measures of social competence. Methods: While viewing social scenes, eye-tracking technology measured visual fixations in 15 cognitively able males with autism and 15 age-, sex-, and verbal IQ-matched control subjects. We reliably coded fixations on 4 regions: mouth, eyes, body, and objects. Statistical analyses compared fixation time on regions of interest between groups and correlation of fixation time with outcome measures of social competence(ie, standardized measures of daily social adjustment and degree of autistic social symptoms). Results: Significant between-group differences were obtained for all 4 regions. The best predictor of autism was reduced eye region fixation time. Fixation on mouths and objects was significantly correlated with social functioning: increased focus on mouths predicted improved social adjustment and less autistic social impairment, whereas more time on objects predicted the opposite relationship. Conclusions: When viewing naturalistic social situations, individuals with autism demonstrate abnormal patterns of social visual pursuit consistent with reduced salience of eyes and increased salience of mouths, bodies, and objects. Fixation times on mouths and objects but not on eyes are strong predictors of degree of social competence.
来源出版物:Archives of General Psychiatry, 2002, 59(9): 809-816
被引频次:699
Infantile autism: A genetic study of 21 twin pairs
Folstein, S; Rutter, M
Abstract: A systematic study was made of a representative group of 21 same-sexed twin pairs(11 MZ and 10 DZ) in which at least one twin showed the syndrome of infantile autism. There was a 36 per cent pair-wise concordance rate for autism in MZ pairs compared with o per cent concordance in DZ pairs. The concordance for cognitive abnormalities was 82 per cent in MZ pairs and 10 per cent in DZ pairs. It was concluded that there were important hereditary influences concerning a cognitive deficit which included but was not restricted to autism. In 12 out of 17 pairs discordant for autism, the presence of autism was associated with a biological hazard liable to cause brain damage. It was concluded that brain injury in the infancy period may lead to autism on its own or in combination with a genetic predisposition. Uncertainty remains on both the mode of inheritance and exactly what is inherited.
来源出版物:Journal of Child Psychology and Psychiatry, 1977, 18(4): 297-321
·推荐论文摘要·
自闭症谱系障碍儿童重复刻板行为研究综述
宁宁,张永盛,杨广学
摘要:重复刻板行为是自闭症谱系障碍的核心缺陷之一,也是自闭症谱系障碍的诊断标准之一。其类型复杂、表现形式多样,对自闭症谱系障碍儿童的社会融合和社会技能的掌握有消极影响。通过对研究重复刻板行为的文献进行梳理,具体整理了重复刻板行为的分类、表现以及成因解释,并对现有研究进行反思,为以后研究提供参考。
关键词:自闭症谱系障碍;重复刻板行为;分类;表现;成因
来源出版物:中国特殊教育, 2015, 2: 46-52
联系邮箱:杨广学,yanggx2789@163.com
孤独症谱系障碍患儿血清25(OH)D水平的检测
杜琳,单玲,王冰,等
摘要:目的:了解孤独症谱系障碍(ASD)患儿维生素D营养状况,探讨维生素D水平与ASD的关系。方法:采用高效液相色谱-串联质谱法对117例新诊断的ASD患儿和109例健康对照儿童进行血清25(OH)D检测,并根据血清25(OH)D水平,将维生素D状况分为正常(>30 ng/mL)、不足(10~30 ng/mL)和缺乏(<10 ng/mL),比较两组儿童维生素D营养状况。结果:ASD患儿25(OH)D水平(19±9 ng/mL)明显低于对照组(36±13 ng/mL),差异有统计学意义(P<0.01)。ASD患儿中维生素D缺乏和不足率为89.7%,明显高于对照组(52.3%),差异有统计学意义(P<0.01)。结论:ASD患儿存在维生素D缺乏或不足,维生素D缺乏和不足有可能是ASD发病的环境/遗传因素。
关键词:孤独症谱系障碍;维生素D;环境因素;遗传因素;儿童
来源出版物:中国当代儿科杂志, 2015, 17(1): 68-71
DSM孤独症谱系障碍诊断分类标准的演变、影响与展望
卜凡帅,徐胜
摘要:准确的诊断分类是孤独症谱系障碍有效干预服务的前提,而准确的诊断分类离不开科学的诊断分类标准。美国《精神障碍诊断与统计手册》(DSM)作为目前使用最广泛的精神类障碍诊断分类标准之一,为基础与临床神经科学、认知与行为科学以及残疾研究等领域的相关人员对包括孤独症谱系障碍在内的精神障碍的诊断分类提供了重要依据。新出版的DSM-5有关孤独症谱系障碍诊断分类标准的变化主要包括障碍分类合并、诊断标准简化以及依障碍程度划分三方面。受此影响,对孤独症谱系障碍的患病群体、临床研究以及教育及相关社会服务等方面带来了一定的变化。未来,纳入社会-心理性因素的考量、与ICD系统进一步兼容以及孤独症谱系障碍诊断分类标准的本土化则可能是ASD诊断分类标准的重点研究领域。
关键词:孤独症谱系障碍;精神障碍诊断与统计手册;诊断分类标准;综述
来源出版物:中国心理卫生杂志, 2015, 29(6): 425-430
青少年孤独症静息态脑突显网络的功能影像学研究
戚晨皓,黄永明,金石,等
摘要:目的:探讨青少年孤独症患者的脑突显网络的异常。方法:对15例青少年孤独症患者(研究组)和15名健康对照者(对照组)进行3.0T静息态脑功能磁共振扫描,使用独立成分分析法对影像学结果进行分析。结果:与对照组相比,研究组突显网络的左眶部额下回、左距状裂周围皮层、左额中回、右楔叶功能连通性减弱,右颞下回、右海马旁回、右枕中回功能连通性增强。结论:青少年孤独症患者的静息态脑突显网络存在多个脑区的功能连通性改变。
关键词:孤独症;功能磁共振;突显网络;独立成分分析
来源出版物:精神医学杂志, 2015, 28(4): 241-244
高功能孤独症儿童的统合型房树人绘画测验特征
李雪;曹白丹;杨文
摘要:目的:探讨高功能孤独症儿童的统合型房树人(S-HTP)绘画测验特征及其社会性发展。方法:对符合美国精神障碍诊断与统计手册第4版(Diagnostic and Statistical Manual of Mental Disorders,Fourth Edition,DSM-Ⅳ)的35例高功能孤独症儿童和年龄、性别、智商相匹配的70例正常对照儿童进行S-HTP绘画测验,分析高功能孤独症儿童S-HTP绘画测验特征(整体评价15个项目、房屋评价9个项目、树木评价5个项目和人物评价14个项目)。结果:在S-HTP绘画测验中,高功能孤独症儿童绘画特征与正常儿童存在明显差异。在主要反映社交互动水平的整体评价中有8个项目存在差异,如孤独症患儿绘画的画面统合性强的比例明显低于正常儿童[5.7%(2/35)vs.67.1%(47/70),P<0.05];在主要反映家庭关系的房屋评价中的有4个项目存在差异,如孤独症儿童绘画中人只在房屋外面的比例明显高于正常儿童[100%(35/35)vs.85.7%(60/70),P<0.05];在主要反映无意识的自我形象的树木评价中有4个项目存在差异,如孤独症儿童树木简化的比例明显高于正常儿童[73.5%(25/35)vs.24.3%(17/70),P<0.05];在主要反映有意识的自我形象和人际关系的人物评价中有8个项目存在差异,如孤独症儿童绘画人物数目2人以上的比例明显低于正常儿童[20.0%(7/35)vs.68.6% (48/70),P<0.05]。结论:高功能孤独症儿童统合型房树人绘画测验绘画特征反映出其社会性发展落后于正常同龄儿童,主要表现在社交互动、人际关系、自我概念和家庭关系方面。
关键词:高功能孤独症;统合型房树人绘画测验;社交互动;横断面研究
来源出版物:中国心理卫生杂志, 2014, 28(4): 260-266
孤独症谱系障碍镜像神经元功能的研究现状
胡霄,黄颐
摘要:镜像神经元假说被认为是一种较全面地解释孤独症谱系障碍的临床症状和神经生物学异常的神经-认知理论。本文综述了国内外近年来在孤独症谱系障碍中镜像神经元功能的研究,分别探讨了神经电生理、神经影像学,神经心理学等方面研究结果,提示这些患者存在部分的镜像神经元功能损害,这些损害与孤独症谱系障碍患者其他的神经认知和社会认知功能损害有着密切关系。
关键词:孤独症谱系障碍;镜像神经元;综述
来源出版物:中国心理卫生杂志, 2014, 28(11): 823-827
联系邮箱:黄颐,huangyi0421@126.com
引导式教育联合融合教育的护理方法对孤独症患儿社交能力的影响
吕复莉,谢晓凤,张玲,等
摘要:目的:建立引导式教育联合融合教育的护理方法,探讨其对孤独症患儿社交能力的影响。方法:选择符合纳入标准的120例孤独症患儿作为研究对象,按照随机化原则分为干预组和对照组各60例。干预组在结构化教育的基础上,结合引导式教育联合融合教育的护理方法,采取医疗机构及社区中心干预与家庭干预相结合;对照组仅接受结构化教育治疗及护理。分别在干预前和干预6个月后,应用孤独症治疗评估量表(Autism Treatment Eva-luation checklist,ATEC)对两组患儿进行评估,判断其对患儿社交能力的影响。结果:干预6个月后,干预组ATEC症状总分差值、社交能力障碍下降程度均高于对照组,差异具有统计学意义(P<0.05)。同时,干预组患儿感知觉项、语言功能的改善明显优于对照组患儿,差异具有统计学意义(P<0.05)。但是在行为方面的得分差异无统计学意义(P>0.05)。结论:引导式教育联合融合教育的护理方法,能激发孤独症患儿的兴趣,促进人格发育,提高社会交流的自信心。
关键词:孤独性障碍;儿童;引导式教育;融合教育
来源出版物:中华护理杂志, 2014, 49(010): 1194-1198
联系邮箱:吴德,845177603@qq.com
孤独症儿童的情绪共情能力及情绪表情注意方式
马伟娜,朱蓓蓓
摘要:研究探讨了孤独症儿童的情绪共情能力及情绪表情注意方式的特点。各选取15名孤独症儿童以及作为对照组的智力障碍儿童和普通儿童各15名,完成情绪共情实验,同时使用生物反馈仪记录自主生理反应,眼动仪记录眼动轨迹。结果发现孤独症儿童对情绪表情的自动模仿及感知能力显著低于智力障碍儿童与普通儿童;对面孔的总注视时间、总注视点数均显著少于智力障碍儿童、普通儿童;对眼部、嘴部的注视时间比及注视点数比均显著低于普通儿童;对高兴和悲伤表情的注意较多而对恐惧则较少。这提示孤独症儿童的情绪共情能力不足、对情绪表情的注意方式异常。
关键词:孤独症儿童;情绪共情;眼动;自主生理反应
来源出版物:心理学报, 2014, 46(4): 528-539
联系邮箱:马伟娜,mwn505@hznu.edu.cn
孤独症儿童的性别差异及其解释模型
关文军,邓猛
摘要:孤独症作为一种由环境和遗传因素共同导致的神经发育障碍,男童发病比例高于女童已成为共识,但对其原因我们仍然知之甚少。本文系统回顾和分析了孤独症儿童在发病率和临床表现上的性别差异,并介绍了目前比较有代表性的几个解释模型。本文认为,孤独症性别差异的解释模型符合人类对残疾本质理解的发展过程,多学科、多方法的综合研究是今后孤独症儿童病理研究的方向,在尚未明晰孤独症病理前,教育和康复对孤独症儿童的积极发展具有不可替代的作用。
关键词:孤独症;性别差异;解释模型
来源出版物:中国特殊教育, 2013, 12: 52-58
Explaining the increase in the prevalence of autism spectrum disorders the proportion attributable to changes in reporting practices
Hansen, SN; Schendel, DE; Parner, ET
Abstract: IMPORTANCE: The prevalence of autism spectrum disorders(ASDs) has increased markedly in recent decades, which researchers have suggested could be caused in part by nonetiologic factors such as changes in diagnosis reporting practices. To our knowledge, no study has quantified the degree to which changes in reporting practices might explain this increase. Danish national health registries have undergone a change in diagnostic criteria in 1994 and the inclusion of outpatient contacts to health registries in 1995. OBJECTIVE: To quantify the effect of changes in reporting practices in Denmark on reported ASD prevalence. DESIGN, SETTING, AND PARTICIPANTS: We used a population-based birth cohort approach that includes information on all individuals with permanent residence in Denmark. We assessed all children born alive from January 1, 1980, through December 31, 1991, in Denmark(n=677915). The children were followed up from birth until ASD diagnosis, death, emigration, or the end of follow-up on December 31, 2011, whichever occurred first. The analysis uses a stratified Cox proportional hazards regression model with the changes in reporting practices modeled as time-dependent covariates. EXPOSURES: The change in diagnostic criteria in 1994 and the inclusion of outpatient diagnoses in 1995. MAIN OUTCOMES AND MEASURES: Autism spectrum disorders. RESULTS: For Danish children born during the study period, 33%(95% CI, 0-70%) of the increase in reported ASD prevalence could be explained by the change in diagnostic criteria alone; 42%(95% CI, 14%-69%), by the inclusion of outpatient contacts alone; and 60%(95% CI, 33%-87%), by the change in diagnostic criteria and the inclusion of outpatient contacts. CONCLUSIONS AND RELEVANCE: Changes in reporting practices can account for most(60%) of the increase in the observed prevalence of ASDs in children born from 1980 through 1991 in Denmark. Hence, the study supports the argument that the apparent increase in ASDs in recent years is in large part attributable to changes in reporting practices.
来源出版物:Jama Pediatrics, 2015, 169(1): 56-62
联系邮箱:Hansen, SN; stefanh@biostat.au.dk
Severe multisensory speech integration deficits in high-functioning school-aged children with autism spectrum disorder(ASD) and their resolution during early adolescence
Foxe, JJ; Molholm, S; Del Bene, VA; et al.
Abstract: Under noisy listening conditions, visualizing a speaker’s articulations substantially improves speech intelligibility. This multisensory speech integration ability is crucial to effective communication, and the appropriate development of this capacity greatly impacts a child's ability to successfully navigate educational and social settings. Research shows that multisensory integration abilities continue developing late into childhood. The primary aim here was to track the development of these abilities in children with autism, since multisensory deficits are increasingly recognized as a component of the autism spectrum disorder(ASD) phenotype. The abilities of high-functioning ASD children(n=84) to integrate seen and heard speech were assessed cross-sectionally, while environmental noise levels were systematically manipulated, comparing them with age-matched neurotypical children(n=142). Severe integration deficits were uncovered in ASD, which were increasingly pronounced as background noise increased. These deficits were evident in school-aged ASD children(5–12 year olds), but were fully ameliorated in ASD children entering adolescence(13–15 year olds). The severity of multisensory deficits uncovered has important implications for educators and clinicians working in ASD. We consider the observation that the multisensory speech system recovers substantially in adolescence as an indication that it is likely amenable to intervention during earlier childhood, with potentially profound implications for the development of social communication abilities in ASD children.
关键词:autism spectrum disorders; cross-modal; development; sensory integration; speech-in-noise
来源出版物:Cerebral Cortex, 2015, 25(2): 298-312
联系邮箱:Foxe, JJ; john.foxe@einstein.yu.edu
The idiosyncratic brain: Distortion of spontaneous connectivity patterns in autism spectrum disorder
Hahamy, A; Behrmann, M; Malach, R
Abstract: Autism spectrum disorder(ASD) has been associated with a reduction in resting state functional connectivity, though this assertion has recently been challenged by reports of increased connectivity in ASD. To address these contradictory findings, we examined both inter-and intrahemispheric functional connectivity in several resting state data sets acquired from adults with high-functioning ASD and matched control participants. Our results reveal areas of both increased and decreased connectivity in multiple ASD groups as compared to control groups. We propose that this heterogeneity stems from a previously unrecognized ASD characteristic: idiosyncratic distortions of the functional connectivity pattern relative to the typical, canonical template. The magnitude of an individual's pattern distortion in homotopic interhemispheric connectivity correlated significantly with behavioral symptoms of ASD. We propose that individualized alterations in functional connectivity organization are a core characteristic of high-functioning ASD, and that this may account for previous discrepant findings.
来源出版物:Nature Neuroscience, 2015, 18(2): 302-309
联系邮箱:Malach, R; rafi.malach@gmail.com
Heritability of autism spectrum disorder in a UK population-based twin sample
Colvert, E; Tick, B; McEwen, F; et al.
Abstract: IMPORTANCE: Most evidence to date highlights the importance of genetic influences on the liability to autism and related traits. However, most of these findings are derived from clinically ascertained samples, possibly missing individuals with subtler manifestations, and obtained estimates may not be representative of the population. OBJECTIVES: To establish the relative contributions of genetic and environmental factors in liability to autism spectrum disorder(ASD) and a broader autism phenotype in a large population-based twin sample and to ascertain the genetic/environmental relationship between dimensional trait measures and categorical diagnostic constructs of ASD. DESIGN, SETTING, AND PARTICIPANTS: We used data from the population-based cohort Twins Early Development Study, which included all twin pairs born in England and wales from January 1, 1994, through December 31, 1996. We performed joint continuousordinal liability threshold model fitting using the full information maximum likelihood method to estimate genetic and environmental parameters of covariance. Twin pairs underwent the following assessments: the Childhood Autism Spectrum Test(CAST)(6423 pairs; mean age, 7.9 years), the Development and Well-being Assessment(DAWBA)(359 pairs; mean age, 10.3 years), the Autism Diagnostic Observation Schedule(ADOS)(203 pairs; mean age, 13.2 years), the Autism Diagnostic Interview- Revised(ADI-R)(205 pairs; mean age, 13.2 years), and a best-estimate diagnosis(207 pairs). MAIN OUTCOMES AND MEASURES: Participants underwent screening using a population-based measure of autistic traits(CAST assessment), structured diagnostic assessments(DAWBA, ADI-R, and ADOS), and a best-estimate diagnosis. RESULTS: On all ASD measures, correlations among monozygotic twins(range, 0.77-0.99) were significantly higher than those for dizygotic twins(range, 0.22-0.65), giving heritability estimates of 56% to 95%. The covariance of CAST and ASD diagnostic status(DAWBA, ADOS and best-estimate diagnosis) was largely explained by additive genetic factors(76%-95%). For the ADI-R only, shared environmental influences were significant(30% [95% CI, 8%-47%]) but smaller than genetic influences(56% [95% CI, 37%-82%]). CONCLUSIONS AND RELEVANCE: The liability to ASD and a more broadly defined high-level autism trait phenotype in this large population-based twin sample derives primarily from additive genetic and, to a lesser extent, nonshared environmental effects. The largely consistent results across different diagnostic tools suggest that the results are generalizable across multiple measures and assessment methods. Genetic factors underpinning individual differences in autismlike traits show considerable overlap with genetic influences on diagnosed ASD.
来源出版物:Jama Psychiatry, 2015, 72(5): 415-423
联系邮箱:Tick, B; beata.b.tick@kcl.ac.uk
Genotype to phenotype relationships in autism spectrum disorders
Chang, J; Gilman, SR; Chiang, AH; et al.
Abstract: Autism spectrum disorders(ASDs) are characterized by phenotypic and genetic heterogeneity. Our analysis of functional networks perturbed in ASD suggests that both truncating and nontruncating de novo mutations contribute to autism, with a bias against truncating mutations in early embryonic development. We find that functional mutations are preferentially observed in geneslikely to be haploinsufficient. Multiple cell types and brain areas are affected, but the impact of ASD mutations appears to be strongest in cortical interneurons, pyramidal neurons and the medium spiny neurons of the striatum, implicating cortical and corticostriatal brain circuits. In females, truncating ASD mutations on average affect genes with 50%-100% higher brain expression than in males. Our results also suggest that truncating de novo mutations play a smaller role in the etiology of high-functioning ASD cases. Overall, we find that stronger functional insults usually lead to more severe intellectual, social and behavioral ASD phenotypes.
来源出版物:Nature Neuroscience, 2015, 18(2): 191-198
联系邮箱:Vitkup, D; dv2121@columbia.edu
Autism
Lai, MC; Lombardo, MV; Baron-Cohen, S; et al.
Abstract: Autism is a set of heterogeneous neurodevelopmental conditions, characterised by early-onset difficulties in social communication and unusually restricted, repetitive behaviour and interests. The worldwide population prevalence is about 1%. Autism affects more male than female individuals, and comorbidity is common(>70% have concurrent conditions). Individuals with autism have atypical cognitive profiles, such as impaired social cognition and social perception, executive dysfunction, and atypical perceptual and information processing. These profiles are underpinned by atypical neural development at the systems level. Genetics has a key role in the aetiology of autism, in conjunction with developmentally early environmental factors. Large-effect rare mutations and small-effect common variants contribute to risk. Assessment needs to be multi- disciplinary and developmental, and early detection is essential for early intervention. Early comprehensive and targeted behavioural interventions can improve social communication and reduce anxiety and aggression. Drugs can reduce comorbid symptoms, but do not directly improve social communication. Creation of a supportive environment that accepts and respects that the individual is different is crucial.
来源出版物:Lancet, 2014, 383(9920): 896-910
联系邮箱:Lai, MC; mcl45@cam.ac.uk
Convergence of genes and cellular pathways dysregulated in autism spectrum disorders
Pinto, D; Delaby, E; Merico, D; et al.
Abstract: Rare copy-number variation(CNV) is an important source of risk for autism spectrum disorders(ASDs). We analyzed 2446 ASD-affected families and confirmed an excess of genic deletions and duplications in affected versus control groups(1.41-fold, P=1.0 × 10-5) and an increase in affected subjects carrying exonic pathogenic CNVs overlapping known loci associated with dominant or X-linked ASD and intellectual disability(odds ratio=12.62, P=2.7×10-15, ~3% of ASD subjects). Pathogenic CNVs, often showing variable expressivity, included rare de novo and inherited events at 36 loci, implicating ASD-associated genes(CHD2, HDAC4, and GDI1) previously linked to other neurodevelopmental disorders, as well as other genes such as SETD5, MIR137, andHDAC9. Consistent with hypothesized gender-specific modulators, females with ASD were more likely to have highly penetrant CNVs(P=0.017) and were also overrepresented among subjects with fragile X syndrome protein targets(P=0.02). Genes affected by de novo CNVs and/or loss-of-function single-nucleotide variants converged on networks related to neuronal signaling and development, synapse function, and chromatin regulation.
来源出版物:The American Journal of Human Genetics, 2014, 94(5): 677-694
联系邮箱:Betancur, C; catalina.betancur@inserm.fr
The familial risk of autism
Sandin, S; Lichtenstein, P; Kuja-Halkola, R; et al.
Abstract: IMPORTANCE: Autism spectrum disorder(ASD) aggregates in families, but the individual risk and to what extent this is caused by genetic factors or shared or nonshared environmental factors remains s unresolved. OBJECTIVE: To provide estimates of familial aggregation and heritability of ASD. DESIGN, SETTING, AND PARTICIPANTS: A population-based cohort including 2049973 Swedish children born 1982 through 2006. We identified 37570 twin pairs, 2642064 full sibling pairs, 432281 maternal and 445531 paternal half sibling pairs, and 5799875 cousin pairs. Diagnoses of ASD to December 31, 2009 were ascertained. MAIN OUTCOMES AND MEASURES: The relative recurrence risk(RRR) measures familial aggregation of disease. The RRR is the relative risk of autism in a participant with a sibling or cousin who has the diagnosis(exposed) compared with the risk in a participant with no diagnosed family member(unexposed). We calculated RRR for both ASD and autistic disorder adjusting for age, birth year, sex, parental psychiatric history, and parental age. We estimated how much of theprobability of developing ASD can be related to genetic(additive and dominant) and environmental(shared and nonshared) factors. RESULTS: In the sample, 14516 children were diagnosed with ASD, of whom 5689 had autistic disorder. The RRR and rate per 100000 person-years for ASD among monozygotic twins was estimated to be 153.0(95% CI, 56.7-412.8; rate, 6274 for exposed vs 27 for unexposed); for dizygotic twins, 8.2(95% CI, 3.7-18.1; rate, 805 for exposed vs 55 for unexposed); for full siblings, 10.3(95% CI, 9.4-11.3; rate, 829 for exposed vs 49 for unexposed); for maternal half siblings, 3.3(95% CI, 2.6-4.2; rate, 492 for exposed vs 94 for unexposed); for paternal half siblings, 2.9(95% CI, 2.2-3.7; rate, 371 for exposed vs 85 for unexposed); and for cousins, 2.0(95% CI, 1.8-2.2; rate, 155 for exposed vs 49 for unexposed). The RRR pattern was similar for autistic disorder but of slightly higher magnitude. We found support for a disease etiology including only additive genetic and nonshared environmental effects. The ASD heritability was estimated to be 0.50(95% CI, 0.45-0.56) and the autistic disorder heritability was estimated to 0.54(95% CI, 0.44-0.64). CONCLUSIONS AND RELEVANCE: Among children born in Sweden, the individual risk of ASD and autistic disorder increased with increasing genetic relatedness. Heritability of ASD and autistic disorder were estimated to be approximately 50%. These findings may inform the counseling of families with affected children.
来源出版物:Jama, 2014, 311(17): 1770-1777
联系邮箱:Sandin, S; sven.sandin@ki.se
The contribution of de novo coding mutations to autism spectrum disorder
Iossifov, I; O’Roak, BJ; Sanders, SJ; et al.
Abstract: Whole exome sequencing has proven to be a powerful tool for understanding the genetic architecture of human disease. Here we apply it to more than 2500 simplex families, each having a child with an autistic spectrum disorder. By comparing affected to unaffected siblings, we show that 13% of de novo missense mutations and 43% of de novo likely gene-disrupting(LGD) mutations contribute to 12% and 9% of diagnoses, respectively. Including copy number variants, coding de novo mutations contribute to about 30% of all simplex and 45% of female diagnoses. Almost all LGD mutations occur opposite wild-type alleles. LGD targets in affected females significantly overlap the targets in males of lower intelligence quotient(IQ), but neither overlaps significantly with targets in males of higher IQ. We estimate that LGD mutation in about 400 genes can contribute to the joint class of affected females and males of lower IQ, with an overlapping and similar number of genes vulnerable to contributory missense mutation. LGD targets in the joint class overlap with published targets for intellectual disability and schizophrenia, and are enriched for chromatin modifiers, FMRP- associated genes and embryonically expressed genes. Most of the significance for the latter comes from affected females.
来源出版物:Nature, 2014, 515(7526): 216-221
联系邮箱:Shendure, J; shendure@uw.edu
Patches of disorganization in the neocortex of children with autism
Stoner, R; Chow, ML; Boyle, MP; et al.
Abstract: Background: Autism involves early brain overgrowth and dysfunction, which is most strongly evident in the prefrontal cortex. As assessed on pathological analysis, an excess of neurons in the prefrontal cortex among children with autism signals a disturbance in prenatal development and may be concomitant with abnormal cell type and laminar development. Methods: To systematically examine neocortical architecture during the early years after the onset of autism, we used RNA in situ hybridization with a panel of layer- and cell-type specific molecular markers to phenotype cortical microstructure. We assayed markers for neurons and glia, along with genes that have been implicated in the risk of autism, in prefrontal, temporal, and occipital neocortical tissue from postmortem samples obtained from children with autism and unaffected children between the ages of 2 and 15 years. Results: We observed focal patches of abnormal laminar cytoarchitecture and cortical disorganization of neurons, but not glia, in prefrontal and temporal cortical tissue from 10 of 11 children with autism and from 1 of 11 unaffected children. We observed heterogeneity between cases with respect to cell types that were most abnormal in the patches and the layers that were most affected by the pathological features. No cortical layer was uniformly spared, with the clearest signs of abnormal expression in layers 4 and 5. Three-dimensional reconstruction of layer markers confirmed the focal geometry and size of patches. Conclusions: In this small, explorative study, we found focal disruption of cortical laminar architecture in the cortexes of a majority of young children with autism. Ourdata support a probable dysregulation of layer formation and layer-specific neuronal differentiation at prenatal developmental stages.
来源出版物:New England Journal of Medicine, 2014, 370(13): 1209-1219
联系邮箱:Courchesne, E; ecourchesne@ucsd.edu
Traffic-related air pollution, particulate matter, and autism
Volk, HE; Lurmann, F; Penfold, B; et al.
Abstract: Context: Autism is a heterogeneous disorder with genetic and environmental factors likely contributing to its origins. Examination of hazardous pollutants has suggested the importance of air toxics in the etiology of autism, yet little research has examined its association with local levels of air pollution using residence-specific exposure assignments. Objective: To examine the relationship between traffic-related air pollution, air quality, and autism. Design: This population-based case-control study includes data obtained from children with autism and control children with typical development who were enrolled in the Childhood Autism Risks from Genetics and the Environment study in California. The mother's address from the birth certificate and addresses reported from a residential history questionnaire were used to estimate exposure for each trimester of pregnancy and first year of life. Traffic-related air pollution was assigned to each location using a line-source air-quality dispersion model. Regional air pollutant measures were based on the Environmental Protection Agency’s Air Quality System data. Logistic regression models compared estimated and measured pollutant levels for children with autism and for control children with typical development. Setting: Case-control study from California. Participants: A total of 279 children with autism and a total of 245 control children with typical development. Main Outcome Measures: Crude and multivariable adjusted odds ratios(AORs) for autism. Results: Children with autism were more likely to live at residences that had the highest quartile of exposure to traffic-related air pollution, during gestation(AOR, 1.98 [95% CI, 1.20-3.31]) and during the first year of life(AOR, 3.10 [95% CI, 1.76-5.57]), compared with control children. Regional exposure measures of nitrogen dioxide and particulate matter less than 2.5 and 10 mu m in diameter(PM2.5and PM10) were also associated with autism during gestation(exposure to nitrogen dioxide: AOR, 1.81 [95% CI, 1.37-3.09]; exposure to PM2.5: AOR, 2.08 [95% CI, 1.93-2.25]; exposure to PM10: AOR, 2.17 [95% CI, 1.49-3.16) and during the first year of life(exposure to nitrogen dioxide: AOR, 2.06 [95% CI, 1.37-3.09]; exposure to PM2.5: AOR, 2.12 [95% CI, 1.45-3.10]; exposure to PM10: AOR, 2.14 [95% CI, 1.46-3.12]). All regional pollutant estimates were scaled to twice the standard deviation of the distribution for all pregnancy estimates. Conclusions: Exposure to traffic-related air pollution, nitrogen dioxide, PM2.5, and PM10during pregnancy and during the first year of life was associated with autism. Further epidemiological and toxicological examinations of likely biological pathways will help determine whether these associations are causal.
来源出版物:Jama Psychiatry, 2013, 70(1): 71-77
联系邮箱:Volk, HE; hvolk@usc.edu
编辑:王微
【作者单位:1. 中国科学院心理研究所,心理健康重点实验室;2. 中国科学院大学】
Abstract: Processing the human face is at the focal point of most social interactions, yet this simple perceptual task is difficult for individuals with autism, a population that spends limited amounts of time engaged in face-to-face eye contact or social interactions in general. Thus, the study of face processing in autism is not only important because it may be integral to understanding the social deficits of this disorder, but also, because it provides a unique opportunity to study experiential factors related to the functional specialization of normal face processing. In short, autism may be one of the only disorders where affected individuals spend reduced amounts of time engaged in face processing from birth. Using functional MRI, haemodynamic responses during a face perception task were compared between adults with autism and normal control subjects. Four regions of interest(ROIs), the fusiform gyrus(FG), inferior temporal gyrus, middle temporal gyrus and amygdala were manually traced on non-spatially normalized images and the percentage ROI active was calculated for each subject. Analyses in Talairach space were also performed. Overall results revealed either abnormally weak or no activation in FG in autistic patients, as well as significantly reduced activation in the inferior occipital gyrus, superior temporal sulcus and amygdala. Anatomical abnormalities, in contrast, were present only in the amygdala in autistic patients, whose mean volume was significantly reduced as compared with normals. Reaction time and accuracy measures were not different between groups. Thus, while autistic subjects could perform the faceperception task, none of the regions supporting face processing in normals were found to be significantly active in the autistic subjects. Instead, in every autistic patient, faces maximally activated aberrant and individual-specific neural sites(e.g. frontal cortex, primary visual cortex, etc.), which was in contrast to the 100% consistency of maximal activation within the traditional fusiform face area(FFA) for every normal subject. It appears that, as compared with normal individuals, autistic individuals 'see' faces utilizing different neural systems, with each patient doing so via a unique neural circuitry. Such a pattern of individualspecific, scattered activation seen in autistic patients in contrast to the highly consistent FG activation seen in normals, suggests that experiential factors do indeed play a role in the normal development of the FFA.
Abstract: Many studies have supported a genetic etiology for autism. Here we report Mutations in two X-linked genes encoding neuroligins NLGN3 and NLGN4 in siblings with autism-spectrum disorders. These mutations affect cell-adhesion molecules localized at the synapse and suggest that a defect of synapto- genesis may predispose to autism.
Abstract: We tested the hypothesis that de novo copy number variation(CNV) is associated with autism spectrum disorders(ASDs). We performed comparative genomic hybridization(CGH) on the genomic DNA of patients and unaffected subjects to detect copy number variants not present in their respective parents. Candidate genomic regions were validated by higher-resolution CGH, paternity testing, cytogenetics, fluorescence in situ hybridization, and microsatellite genotyping. Confirmed de novo CNVs were significantly associated with autism(P=0.0005). Such CNVs were identified in 12 out of 118(10%) of patients with sporadic autism, in 2 out of 77(3%) of patients with an affected first-degree relative, and in 2 out of 196(1%) of controls. Most de novo CNVs were smaller than microscopic resolution. Affected genomic regions were highly heterogeneous and included mutations of single genes. These findings establish de novo germline mutation as a more significant risk factor for ASD than previously recognized.
Abstract: Autism spectrum disorders(ASDs) are common, heritable neurodevelopmental conditions. The genetic architecture of ASDs is complex, requiring large samples to overcome heterogeneity. Here we broaden coverage and sample size relative to other studies of ASDs by using Affymetrix 10K SNP arrays and 1168 families with at least two affected individuals, performing the largest linkage scan to date while also analyzing copy number variation in these families. Linkage and copy number variation analyses implicate chromosome 11p12-p13 and neurexins, respectively, among other candidate loci. Neurexins team with previously implicated neuroligins for glutamatergic synaptogenesis, highlighting glutamaterelated genes as promising candidates for contributing to ASDs.
Abstract:Two previous epidemiological studies of autistic twins suggested that autism was predominantly genetically determined, although the findings with regard to a broader phenotype of cognitive, and possibly social, abnormalities were contradictory. Obstetric and perinatal hazards were also invoked as environmentally determined aetiological factors. The first British twin sample has been re-examined and a second total population sample of autistic twins recruited. In the combined sample 60% of monozygotic(MZ) pairs were concordant for autism versus no dizygotic(DZ) pairs; 92% of MZ pairs were concordant for a broader spectrum of related cognitive or social abnormalities versus 10% of DZ pairs. The findings indicate that autism is under a high degree of genetic control and suggest the involvement of multiple genetic loci. Obstetric hazards usually appear to be consequences of genetically influenced abnormal development, rather than independent aetiological factors. Few new cases had possible medical aetiologies, refuting claims that recognized disorders are common aetiological influences.