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.

 孤獨癥患者通常有出色的記憶力、數學技能、或音樂天賦，這常常使專家們驚嘆不已。現在科學家們發現，那些被認為是造成孤獨癥的基因，可能也會造就數學、音樂、和其它方面的天才。

這個發現是從一項對劍橋大學378名學生的關于孤獨癥的研究中得出的。這項研究發現，數學專業中患孤獨癥的學生可以達到非數學專業的七倍。另外，數學專業學生的同胞手足中患孤獨癥的，是非數學專業的五倍。

如果被證實了的話，它就可以解釋為什么孤獨癥---一種人際交流障礙---仍然存在于各種社會形態中。很有可能這些基因通常是有益的，只有出現在錯誤的組合中才會造成孤獨癥。指導這項研究的劍橋孤獨癥研究所所長Simon Baron-Cohen教授說：‘我們對孤獨癥的認識正在經歷一個轉變。’

‘顯然，基因對孤獨癥的形成有著重要的作用，而同樣的基因也與某些聰明才智相關聯。’

長期以來，科學家們對于孤獨癥與某些智力天賦之間顯著的相關性很感興趣。這也使得孤獨癥在大眾文化中成了熱門，產生了由達斯汀·霍夫曼和湯姆·克魯斯主演的《雨人》一類的影片，以及《夜色下的死狗之謎》（The Curious Incident of the Dog in the Nighttime）一類的故事書。

有些孤獨癥患者因他們的創造力而名噪天下。34歲的英國藝術家Stephen Wiltshire小的時候不說話，被診斷為典型孤獨癥。他從五歲起開始畫畫，很快就把城市景色畫了個遍。他的驚人業績之一，是在乘直升機在東京上空短暫飛行之后，僅憑記憶將東京全景詳盡地描畫出來。從那以后他開辦了自己的畫廊。

孤獨癥和與之相關的阿斯伯格綜合癥是很常見的精神疾患，在英國大約有六十萬患者。男孩患孤獨癥的機會是女孩的4倍。孤獨癥患者可能會有一些特殊的才能，但是他們也很容易焦慮，產生強迫行為和其他問題。這些問題給他們造成的痛苦要大大超過他們在才智上的優勢。

孤獨癥可以在家庭的幾代人中出現的事實，說明它的成因有部分的遺傳因素。但是根據進化理論，這種致病基因應當早已被從人口中淘汰掉了。劍橋的研究暗示了為什么這些基因沒有被淘汰的原因---因為在某些基因組合中，這些基因是有益的。

我們需要謹慎對待這樣的研究結果，因為這類研究樣本數量很小。在劍橋的這項研究中，378個數學專業的學生里有7個是孤獨癥。相比之下，控制組的414個學生中只有一個是孤獨癥。

然而，其它的研究也發現了類似的模式。Baron-Cohen說：‘有些研究發現，在孤獨癥兒童的父親和祖父中，以工程為職業的人是非孤獨癥家庭中的兩倍。學習自然科學的學生比學習人文科學的學生有更多的親人患孤獨癥。’

他的這項研究是在英國皇家學會上周（譯注：本文發表于2008年10月5日）的一次會議上宣讀的。它剛好與另一項研究的發現不謀而合。那項研究認為可能有將近三分之一的孤獨癥患者有‘奇能’。

Patricia Howlin，倫敦國王學院精神病研究所的臨床兒童心理學教授，研究了137個孤獨癥患者；其中39人（占29%）有特殊才能。最常見的才能是超常的記憶力。

她說：‘過去人們認為只有百分之五到十的患者有這樣的才能，但是從來沒有人認真地測量過。看來這樣的人很多。如果我們能給他們以適當的培養和引導，就會有更多的患者能夠獨立生活，甚至成為成功人士。’

這種認為孤獨癥有它好的一面的觀點受到了一些孤獨癥人士的歡迎。這類人士對自己被視為‘殘疾’甚為反感，所以他們將非孤獨癥人士稱為‘神經標準人（Neurotypicals）’，以說明在孤獨癥人士眼中，他們才是有缺陷的一類。

悉尼大學心智中心主任Allan Snyder教授說：‘在孤獨癥譜系中，一端是典型的有嚴重心智缺陷的患者，而另一端是獲諾貝爾獎的天才。這兩個極端的患者都有著孤獨癥的核心特征，比如注重細節，著魔于某些興趣，以及無法從他人的角度思考問題。’

61歲的Temple Grandin小時候被診斷為孤獨癥，而她現在是科羅拉多州立大學的動物學教授。她說：‘患有孤獨癥的人們在人類進化和文化方面一直扮演著重要的角色。在有計算機以前，設計一個大教堂就需要一個有類似于孤獨癥患者那樣的記憶力的設計師。像牛頓和愛因斯坦這樣的科學家也表現得很像孤獨癥患者。我們全世界的人都應當感謝那些設計計算機和編寫程序的人們，他們中間的很多人都表現出孤獨癥的性格。’

對Baron-Cohen來說，下一步是去發現與孤獨癥相關的基因；他將與國王學院的Ian Craig教授合作，對大量的孤獨癥患者和數學家進行DNA掃描。