Many of the seemingly disparate genetic mutations recently discovered in autism share common underlying mechanisms, according to the results of a large international study published on the 11 July. The mutations seem to disrupt genes that are active in the developing brain and which are turned on and off in response to experience.

The researchers, who are based at Harvard University, took advantage of a short cut to genetic discovery by sampling families in which parents are cousins. This increases the likelihood that offspring will inherit rare mutations.

They found genes and mutations associated with autism in 88 large families from the Arab Middle East, Turkey and Pakistan, in which cousins married and had children with the disorder. The results appear in the journal Science.

Christopher Walsh, lead author, said: “To map a gene for autism in American families, averaging two to three kids per family, you would need to pool many families. In [the Middle East] one family alone may be enough to definitively localise a gene.”

“There appear to be many separate mutations involved, with each family having a different genetic cause,” added Thomas Insel, director of the US National Institute of Mental Health. “The one unifying observation is that all the relevant mutations could disrupt the formation of vital neural connections during a critical period when experience is shaping the [young child's] developing brain.”

7月11日发表的一项大型国际研究结果显示，最近在自闭症患者中发现的很多基因突变虽然看似彼此不同，实际上却有共同的内在机制。这些突变可能会破坏在大脑发育中表现活跃的基因，面对不同的外部体验，人体会选择是否让这些基因发挥作用。

来自美国哈佛大学(Harvard University)的研究人员在基因发现中走了一条捷径：只对父母是表亲或堂亲的家庭进行采样，从而增加了子女遗传罕见突变的可能性。

在88个父母为表亲或堂亲、子女患有自闭症的中东阿拉伯、土耳其和巴基斯坦的大家庭中，研究人员发现了与自闭症有关的基因及基因突变。他们的研究结果发表在《科学》(Science) 杂志上。

该论文的第一作者克里斯托弗?沃尔什(Christopher Walsh)说：“美国家庭一般有两三个子女，要绘制这些美国家庭的自闭症基因图，你需要汇集很多家庭样本。而（在中东）只对一个家庭进行研究，可能就足以确定基因所在位置。”

“由于每个家庭的遗传因素各不相同，似乎会涉及许多不同的基因突变，”美国国家心理健康研究所(National Institute of Mental Health)所长托马斯?因泽尔(Thomas Insel)补充道。“一项相同的观察结果是，在外部体验令幼儿大脑发育定型的关键时期，所有相关基因突变都可能破坏至关重要的神经连接的形成。”