自闭症是一种具有高度遗传性的神经发育疾病，然而迄今所发现的特定易感基因非常少。现在，在一组1,031个多元化自闭症家庭中利用50万个全genomics/" target="_blank">基因组SNP（单核苷酸多态性）所进行的一次全基因组扫描，显示了与自闭症相关的重要关联。所发现的关联区域为罕见变异筛选提供了目标，同时研究人员还在染色体5p15上的SEMA5A 和TAS2R1之间发现了一个新的关联。SEMA5A的表达被发现在自闭症患者脑中减少，从而进一步证实它是一个自闭症易感基因。（生物谷Bioon.com）

生物谷推荐原始出处：

Nature 461, 802-808 (8 October 2009) | doi:10.1038/nature08490

A genome-wide linkage and association scan reveals novel loci for autism

Lauren A. Weiss1,2,77,75, Dan E. Arking3,77 & The Gene Discovery Project of Johns Hopkins & the Autism Consortium

Although autism is a highly heritable neurodevelopmental disorder, attempts to identify specific susceptibility genes have thus far met with limited success1. Genome-wide association studies using half a million or more markers, particularly those with very large sample sizes achieved through meta-analysis, have shown great success in mapping genes for other complex genetic traits. Consequently, we initiated a linkage and association mapping study using half a million genome-wide single nucleotide polymorphisms (SNPs) in a common set of 1,031 multiplex autism families (1,553 affected offspring). We identified regions of suggestive and significant linkage on chromosomes 6q27 and 20p13, respectively. Initial analysis did not yield genome-wide significant associations; however, genotyping of top hits in additional families revealed an SNP on chromosome 5p15 (between SEMA5A and TAS2R1) that was significantly associated with autism (P = 2*10-7). We also demonstrated that expression of SEMA5A is reduced in brains from autistic patients, further implicating SEMA5A as an autism susceptibility gene. The linkage regions reported here provide targets for rare variation screening whereas the discovery of a single novel association demonstrates the action of common variants.