孤独症是一种发生于儿童早期的精神发育障碍性疾病，至今病因不明。催产素（OXT）和精氨酸后叶加压素（AVP）是调节社会交往的重要物质，其受雌、雄激素调控。国外学者与我实验室发现孤独症儿童血浆内OXT与AVP水平降低，其母亲相对正常儿童母亲也明显降低。最新进展显示环境因素在孤独症的致病因素中占55%，母亲的内环境很可能对孤独症儿童胚胎时期脑发育有直接影响。因此，母体内OXT/AVP的缺乏或调节异常是否是造成子代发病的原因是本研究的重要内容。本研究分为两部分：回顾性研究拟招募正常与孤独症儿童及其母亲，而前瞻性研究则招募孕早期妇女，留取其血浆，待其生产并抚养孩子至2.5岁后对其子女做孤独症筛查。分析正常或孤独症儿童及其母亲基础状态与孕早期血浆雌/雄激素、OXT/AVP水平以及儿童血细胞OXT/AVP及其受体基因甲基化模式间的异同。通过本研究寻找影响孤独症发病的高危因素，为孤独症的预防工作提供参考。

Autism is a developmental psychiatric disorder occurred early in the childhood. The disease receives more attention in recent years due to a relatively high prevalence rate, poor prognosis and lack of satisfactory therapy. OXT and AVP are known to be involved in mediating social interactions. Plasma OXT and AVP levels are regulated by both estrogen and testosterone. It has been reported that the plasma level of OXT is reduced in autistic children. We have previously reported that the plasma level of AVP is lower in both artistic children and their mothers. It is estimated recently that genetic factors only contribute 38% in causing autism. The environmental factors play a more important role (55%). We hypothesize that the abnormal environment such as abnormal levels or regulation of OXT and/or VAP in the mother during pregnancy may play an important role in the development of autism. There are two parts of the proposed study. 1) to study the hormonal changes in normal and autistic children and in their mothers. 2) In the prospective study we will collect blood samples from women in early pregnancy. We will screen the children for autism when they become two years old. The plasma samples from normal and autistic children will be analyzed for OXT and AVP. The levels of methylation of receptor genes of OXT and AVP will also be determined. In addition, the plasma levels of estrogen, testosterone, OXT and AVP in basal state and during pregnancy will also be determined. The aims of the study are to identify the causal factors contributing to the development of autism and to estimate the risk of having an autistic children based on biomarkers during pregnancy.