摘要：美国一项最新研究成果显示，自闭症不仅与遗传因素有关，而且可能与环境因素有很大的关系。
这项研究是由美国斯坦福大学的研究人员完成的，研究涉及192对双胞胎，其中54对为同卵双胞胎，138对为异卵双胞胎。同卵双胞胎中，约42.5%的男性双胞胎及43%的女性双胞胎均患有自闭症；异卵双胞胎中，约12.9%的男性双胞胎及20%的女性双胞胎均患有自闭症。
研究报告的主要作者、斯坦福大学精神病学及行为科学副教授约基姆·哈尔迈尔指出，如果自闭症完全由基因因素造成，那么基因特征完全相同的同卵双胞胎都会患自闭症，但实际情况并非如此。
研究人员认为，基因和环境都是造成自闭症的因素，而且后者产生的作用可能更大。所谓环境因素是指生育年龄、怀孕期间受感染和服药、婴儿体重过轻等。此前一项研究发现，女性在怀孕期间服抗抑郁药，其孩子出生后患自闭症的几率会提高。
这项研究成果刊登在近日出版的《普通精神病学文献》网络版上。
生物探索推荐英文论文摘要：
doi:10.1001/archgenpsychiatry.2011.76
Genetic Heritability and Shared Environmental Factors Among Twin Pairs With Autism
ABSTRACT
Context Autism is considered the most heritable of neurodevelopmental disorders, mainly because of the large difference in concordance rates between monozygotic and dizygotic twins.
Objective To provide rigorous quantitative estimates of genetic heritability of autism and the effects of shared environment.
Design, Setting, and Participants Twin pairs with at least 1 twin with an autism spectrum disorder (ASD) born between 1987 and 2004 were identified through the California Department of Developmental Services.
Main Outcome Measures Structured diagnostic assessments (Autism Diagnostic Interview–Revised and Autism Diagnostic Observation Schedule) were completed on 192 twin pairs. Concordance rates were calculated and parametric models were fitted for 2 definitions, 1 narrow (strict autism) and 1 broad (ASD).
Results For strict autism, probandwise concordance for male twins was 0.58 for 40 monozygotic pairs (95% confidence interval [CI], 0.42-0.74) and 0.21 for 31 dizygotic pairs (95% CI, 0.09-0.43); for female twins, the concordance was 0.60 for 7 monozygotic pairs (95% CI, 0.28-0.90) and 0.27 for 10 dizygotic pairs (95% CI, 0.09-0.69). For ASD, the probandwise concordance for male twins was 0.77 for 45 monozygotic pairs (95% CI, 0.65-0.86) and 0.31 for 45 dizygotic pairs (95% CI, 0.16-0.46); for female twins, the concordance was 0.50 for 9 monozygotic pairs (95% CI, 0.16-0.84) and 0.36 for 13 dizygotic pairs (95% CI, 0.11-0.60). A large proportion of the variance in liability can be explained by shared environmental factors (55%; 95% CI, 9%-81% for autism and 58%; 95% CI, 30%-80% for ASD) in addition to moderate genetic heritability (37%; 95% CI, 8%-84% for autism and 38%; 95% CI, 14%-67% for ASD).
Conclusion Susceptibility to ASD has moderate genetic heritability and a substantial shared twin environmental component.
