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Some people with autism have amazed experts with their outstanding memories, mathematical skills or musical talent. Now scientists have found that the genes thought to cause autism may also confer mathematical, musical and other skills on people without the condition.
The finding has emerged from a study of autism among 378 Cambridge University students, which found the condition was up to seven times more common among mathematicians than students in other disciplines. It was also five times more common in the siblings of mathematicians.
If confirmed, it could explain why autism - a disability that makes it hard to communicate with, and relate to, others - continues to exist in all types of society. It suggests the genes responsible are usually beneficial, causing the disease only if present in the wrong combinations. “Our understanding of autism is undergoing a transformation,” said Professor Simon Baron-Cohen, director of the autism research centre at Cambridge, who led the study.
“It seems clear that genes play a significant role in the causes of autism and that those genes are also linked to certain intellectual skills.”
Scientists have long been intrigued by the apparent association between autism and intellectual gifts in specific fields. This has made autism a hot topic in popular culture, from films such as Rain Man, which starred Dustin Hoffman and Tom Cruise, to books such as The Curious Incident of the Dog in the Nighttime.
Some people with autism have become renowned for their creativity. The British artist Stephen Wiltshire, 34, was mute as a child and diagnosed with classic autism. He began drawing at the age of five and soon completed cityscapes. One of his feats was to draw a stunningly detailed panoramic view of Tokyo from memory after a short helicopter ride. He has since opened a gallery.
Autism and the related Asperger’s syndrome are among the commonest mental afflictions, affecting about 600,000 Britons. Boys are four times as likely as girls to develop it. Autistic people can have special skills but they also tend to suffer from anxiety, obsessive behaviour and other problems that far outweigh any advantages.
The fact that autism runs in families shows that it is partly genetic in origin, but evolutionary theory suggests genes causing such a debilitating conditions ought to have been weeded out of the population. The Cambridge study hints at why this has not happened, suggesting that with variations in the way they are combined, such genes are beneficial.
On their own, such studies have to be treated cautiously because the numbers involved are small. In the Cambridge study, seven of 378 maths students were found to be autistic, compared with only one among the 414 students in the control group.
Other studies, however, have found similar patterns. Baron-Cohen, whose cousin Sacha Baron Cohen is the comic actor behind the Ali G and Borat characters, said: “Separate studies have shown that the fathers and grandfathers of children with autism are twice as likely to work in engineering. Science students also have more relatives with autism than those in the humanities.”
His research, set out last week in a meeting at the Royal Society, coincides with separate research showing nearly a third of people with autism may have “savant” skills.
Patricia Howlin, professor of clinical child psychology at the Institute of Psychiatry at King’s College London, studied 137 people with autism; 39 of them (29%) possessed an exceptional mental skill. The most common was outstanding memory.
She said: “It had been thought that only about 5%-10% of people with autism had such skills, but nobody had measured it properly, and it seems the number is far higher. If we could foster these skills, many more people with autism could live independently and even become high achievers.”
The idea that autism may have positive aspects is finding favour among some of those with the condition. Some resent being labelled disabled and have begun describing those without autism as “neurotypicals” to make the point that they could be the ones missing out.
Professor Allan Snyder, director of the centre for the mind at the University of Sydney, said: “Autism ranges from the classical picture of severe mental impairment at one end of the spectrum to Nobel prize-win-ning genius at the other. Both extremes have core autistic features, such as preoccupation with detail, obsessional interests and difficulties in understanding other people’s perspectives.”
Temple Grandin, 61, was diagnosed with autism as a child and is now professor of animal sciences at Colorado State University. She said: “People with autism have played a vital role in human evolution and culture. Before computers it would have taken someone with an autistic-type memory to design great cathedrals, while scientists such as Isaac Newton and Albert Einstein show every sign of having been autistic. The world owes a great deal to those who design and programme computers, many of whom show autistic traits.”
For Baron-Cohen the next step is to find the genes linked with autism; he is working with Professor Ian Craig of King’s College to scan the DNA of hundreds of autistic people - and of mathematicians.
孤独症患者通常有出色的记忆力、数学技能、或音乐天赋，这常常使专家们惊叹不已。现在科学家们发现，那些被认为是造成孤独症的基因，可能也会造就数学、音乐、和其它方面的天才。
这个发现是从一项对剑桥大学378名学生的关于孤独症的研究中得出的。这项研究发现，数学专业中患孤独症的学生可以达到非数学专业的七倍。另外，数学专业学生的同胞手足中患孤独症的，是非数学专业的五倍。
如果被证实了的话，它就可以解释为什么孤独症---一种人际交流障碍---仍然存在于各种社会形态中。很有可能这些基因通常是有益的，只有出现在错误的组合中才会造成孤独症。指导这项研究的剑桥孤独症研究所所长Simon Baron-Cohen教授说：‘我们对孤独症的认识正在经历一个转变。’
‘显然，基因对孤独症的形成有着重要的作用，而同样的基因也与某些聪明才智相关联。’
长期以来，科学家们对于孤独症与某些智力天赋之间显著的相关性很感兴趣。这也使得孤独症在大众文化中成了热门，产生了由达斯汀·霍夫曼和汤姆·克鲁斯主演的《雨人》一类的影片，以及《夜色下的死狗之谜》（The Curious Incident of the Dog in the Nighttime）一类的故事书。
有些孤独症患者因他们的创造力而名噪天下。34岁的英国艺术家Stephen Wiltshire小的时候不说话，被诊断为典型孤独症。他从五岁起开始画画，很快就把城市景色画了个遍。他的惊人业绩之一，是在乘直升机在东京上空短暂飞行之后，仅凭记忆将东京全景详尽地描画出来。从那以后他开办了自己的画廊。
孤独症和与之相关的阿斯伯格综合症是很常见的精神疾患，在英国大约有六十万患者。男孩患孤独症的机会是女孩的4倍。孤独症患者可能会有一些特殊的才能，但是他们也很容易焦虑，产生强迫行为和其他问题。这些问题给他们造成的痛苦要大大超过他们在才智上的优势。
孤独症可以在家庭的几代人中出现的事实，说明它的成因有部分的遗传因素。但是根据进化理论，这种致病基因应当早已被从人口中淘汰掉了。剑桥的研究暗示了为什么这些基因没有被淘汰的原因---因为在某些基因组合中，这些基因是有益的。
我们需要谨慎对待这样的研究结果，因为这类研究样本数量很小。在剑桥的这项研究中，378个数学专业的学生里有7个是孤独症。相比之下，控制组的414个学生中只有一个是孤独症。
然而，其它的研究也发现了类似的模式。Baron-Cohen说：‘有些研究发现，在孤独症儿童的父亲和祖父中，以工程为职业的人是非孤独症家庭中的两倍。学习自然科学的学生比学习人文科学的学生有更多的亲人患孤独症。’
他的这项研究是在英国皇家学会上周（译注：本文发表于2008年10月5日）的一次会议上宣读的。它刚好与另一项研究的发现不谋而合。那项研究认为可能有将近三分之一的孤独症患者有‘奇能’。
Patricia Howlin，伦敦国王学院精神病研究所的临床儿童心理学教授，研究了137个孤独症患者；其中39人（占29%）有特殊才能。最常见的才能是超常的记忆力。
她说：‘过去人们认为只有百分之五到十的患者有这样的才能，但是从来没有人认真地测量过�？蠢凑庋娜撕芏�。如果我们能给他们以适当的培养和引导，就会有更多的患者能够独立生活，甚至成为成功人士。’
这种认为孤独症有它好的一面的观点受到了一些孤独症人士的欢迎。这类人士对自己被视为‘残疾’甚为反感，所以他们将非孤独症人士称为‘神经标准人（Neurotypicals）’，以说明在孤独症人士眼中，他们才是有缺陷的一类。
悉尼大学心智中心主任Allan Snyder教授说：‘在孤独症谱系中，一端是典型的有严重心智缺陷的患者，而另一端是获诺贝尔奖的天才。这两个极端的患者都有着孤独症的核心特征，比如注重细节，着魔于某些兴趣，以及无法从他人的角度思考问题。’
61岁的Temple Grandin小时候被诊断为孤独症，而她现在是科罗拉多州立大学的动物学教授。她说：‘患有孤独症的人们在人类进化和文化方面一直扮演着重要的角色。在有计算机以前，设计一个大教堂就需要一个有类似于孤独症患者那样的记忆力的设计师。像牛顿和爱因斯坦这样的科学家也表现得很像孤独症患者。我们全世界的人都应当感谢那些设计计算机和编写程序的人们，他们中间的很多人都表现出孤独症的性格。’
对Baron-Cohen来说，下一步是去发现与孤独症相关的基因；他将与国王学院的Ian Craig教授合作，对大量的孤独症患者和数学家进行DNA扫描。
