多动症的遗传学研究概述

An Overview on the Genetics of ADHD

多动症多始于儿童期，并能持续至成年期。传统的家庭、双生子和养子女研究表明，多动症是受遗传影响的。双生子研究现在被用来定义多动症表型，分析性别差异，测试基因对持续性和共病的影响，以及研究遗传与环境的互动。多动症的分子遗传学研究集中在功能候选基因的关联分析上。多动症与DRD4和DRD5的关系比较一致。最新的研究也显示COMT的影响。关联分析（1inkageanalysis）显示这些单个基因的影响都不大。这个领域还有待于大规模的“全基因关联”分析。至今为止的证据显示，研究基因-表型关联以及基因与环境互动对多动症的影响将目趋重要。

Attention Deficit Hyperactivity is a childhood-onset disorder that can persist into adult life. Traditional family, twin and adoption studies have shown that ADHD defined both categorically and dimensionally is familial and heritable. Twin studies are now being used to examine ways of defining the ADHD phenotype, to investigate gender differences, the effects on genes on continuity and comorbidity and to consider gene-environment interplay. Molecular genetic findings on ADHD have mainly arisen from functional candidate gene association studies and a number of pooled and meta-analyses have now been conducted. There is consistent evidence of association between ADHD and a dopamine D4 receptor gene VNTR and a dopamine D5 receptor gene microsatellite marker. More recent evidence from different studies and a pooled analysis suggests that conduct problems in those with ADHD is influenced by the COMT va1158/108 met variant. Linkage studies suggest that there are no genes of moderate effect size and findings from large scale whole genome association studies are currently awaited. Overall the evidence to date, suggests that examining gene-phenotype links and testing whether gene variants have modifying effects on the ADHD phenotype are important. The contribution of gene- environment interplay （G x E） to psychopathology is becoming increasingly recognised, although for ADHD little is known on causal environmental risk factors.