2015年经济学人 为何男性患自闭症比例大大高于女性？

Autism

Why it's not “Rain Woman”

Women have fewer cognitive¹ disorders³ than men do because their bodies are better at ignoring the mutations which cause them

AUTISM is a strange condition. Sometimes its symptoms of “social blindness”

(an inability to read or comprehend the emotions of others) occur alone.

This is dubbed⁵ high-functioning autism, or Asperger's syndrome⁶.

Though their fellow men and women may regard them as a bit odd,

high-functioning autists are often successful (sometimes very successful) members of society.

On other occasions, though, autism manifests as part of a range of cognitive problems.

Then, the condition is debilitating⁷. What is common to those on all parts of the so-called autistic spectrum⁸ is that they are more often men than women—

so much more often that one school of thought suggests autism is an extreme manifestation⁹ of what it means, mentally, to be male.

Boys are four times more likely to be diagnosed with autism than girls are. For high-functioning autism, the ratio is seven to one.

Moreover, what is true of autism is true, to a lesser¹¹ extent, of a lot of other neurological and cognitive disorders.

Attention deficit¹² hyperactivity disorder² (ADHD) is diagnosed around three times more often in boys than in girls.

“Intellectual disability”, a catch-all term for congenital low IQ, is 30-50% more common in boys, as is epilepsy.

In fact, these disorders frequently show up in combination.

For instance, children diagnosed with an autistic-spectrum disorder[1] often also receive a diagnosis¹³ of ADHD.

Autism's precise causes are unclear, but genes¹⁴ are important.

Though no mutation⁴ which, by itself, causes autism has yet been discovered,

well over 100 are known that make someone with them more vulnerable to the condition.

Most of these mutations are as common in women as in men,

so one explanation for the divergent incidence is that male brains are more vulnerable than female ones to equivalent levels of genetic¹⁵ disruption.

This is called the female-protective model. The other broad explanation, social-bias theory, is that the difference is illusory.

Girls are being under-diagnosed because of differences either in the ways they are assessed,

or in the ways they cope with the condition, rather than because they actually have it less.

Some researchers claim, for example, that girls are better able to hide their symptoms.

To investigate this question, Sebastien Jacquemont of the University Hospital of Lausanne and his colleagues analysed genetic data from two groups of children with cognitive abnormalities.

Those in one group, 800 strong, were specifically autistic. Those in the other, 16,000 strong, had a range of problems.

Dr Jacquemont has just published his results in the American Journal of Human Genetics.

His crucial finding was that girls in both groups more often had mutations of the sort associated with abnormal neural¹⁶ development than boys did.

This was true both for copy-number variants¹⁷ (CNVs, which are variations in the number of copies in a chromosome¹⁸ of particular sections of DNA¹⁹),

and single-nucleotide variants (SNVs, which are alterations²⁰ to single genetic letters in the DNA message).

On the face of it, this seems compelling evidence for the female-protective model.

Since all the children whose data Dr Jacquemont examined had been diagnosed with problems,

if the girls had more serious mutations than the boys did, that suggests other aspects of their physiology²¹ were covering up the consequences.

Females are thus, if this interpretation²² is correct, better protected from developing symptoms than males are.

And, as further confirmation²³, Dr Jacquemont's findings tally¹⁰ with a study published three years ago,

which found that CNVs in autistic girls spanned more genes (and were thus, presumably, more damaging), than those in autistic boys.

The counter-argument is that if girls are better at hiding their symptoms, only the more extreme female cases might turn up in the diagnosed groups.

If that were true, a greater degree of mutation might be expected in symptomatic girls as a consequence.

However, Dr Jacquemont and his colleagues also found that damaging CNVs were more likely to be inherited from a child's mother than from his or her father.

They interpret this as further evidence of female-protectedness. Autistic symptoms make people of either sex less likely to become parents.

If mothers are the source of the majority of autism-inducing genes in children, it suggests they are less affected²⁴ by them.

None of this, though, explains the exact mechanism²⁵ that makes boys more susceptible²⁶ than girls.

On this question, too, there are two predominant theories.

The first is that males are more sensitive because they have only one X-chromosome.

This makes them vulnerable to mutations on that chromosome, because any damaged genes have no twin to cover for them.

One cognitive disorder, fragile-X syndrome, is indeed much more common in men for this reason.

Dr Jacquemont's study, however, found only a limited role for X-chromosome mutations.

That suggests the genetic basis of the difference is distributed across the whole genome.

The other kind of explanation is anatomical.

It is based on brain-imaging studies which suggest differences between the patterns of internal connection in male and female brains.

Male brains have stronger local connections, and weaker long-range ones, than do female brains.

That is similar to a difference seen between the brains of autistic people and of those who are not.

The suggestion here is that the male-type connection pattern is somehow more vulnerable to disruption by the factors which trigger autism and other cognitive problems.

Why that should be, however, remains²⁷ opaque²⁸.

1 cognitive   

adj.认知的，认识的，有感知的

参考例句：

• As children grow older,their cognitive processes become sharper.孩子们越长越大，他们的认知过程变得更为敏锐。
• The cognitive psychologist is like the tinker who wants to know how a clock works.认知心理学者倒很像一个需要通晓钟表如何运转的钟表修理匠。

2 disorder   

n.紊乱，混乱；骚动，骚乱；疾病，失调

参考例句：

• When returning back,he discovered the room to be in disorder.回家后，他发现屋子里乱七八糟。
• It contained a vast number of letters in great disorder.里面七零八落地装着许多信件。

3 disorders   

n.混乱( disorder的名词复数 )；凌乱；骚乱；（身心、机能）失调

参考例句：

• Reports of anorexia and other eating disorders are on the increase. 据报告，厌食症和其他饮食方面的功能紊乱发生率正在不断增长。 来自《简明英汉词典》
• The announcement led to violent civil disorders. 这项宣布引起剧烈的骚乱。 来自《简明英汉词典》

4 mutation   

n.变化，变异，转变

参考例句：

• People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
• So far the discussion has centered entirely around mutation in the strict sense.到目前为止，严格来讲，讨论完全集中于围绕突变问题上。

5 dubbed   

v.给…起绰号( dub的过去式和过去分词 )；把…称为；配音；复制

参考例句：

• Mathematics was once dubbed the handmaiden of the sciences. 数学曾一度被视为各门科学的基础。
• Is the movie dubbed or does it have subtitles? 这部电影是配音的还是打字幕的？ 来自《简明英汉词典》

6 syndrome   

n.综合病症；并存特性

参考例句：

• The Institute says that an unidentified virus is to blame for the syndrome. 该研究所表示,引起这种综合症的是一种尚未确认的病毒。
• Results indicated that 11 fetuses had Down syndrome. 结果表明有11个胎儿患有唐氏综合征。

7 debilitating   

a.使衰弱的

参考例句：

• The debilitating disease made him too weak to work. 这个令他衰弱的病，使他弱到没有办法工作。
• You may soon leave one debilitating condition or relationship forever. 你即将永远地和这段霉运说拜拜了。

8 spectrum   

n.谱，光谱，频谱；范围，幅度，系列

参考例句：

• This is a kind of atomic spectrum.这是一种原子光谱。
• We have known much of the constitution of the solar spectrum.关于太阳光谱的构成，我们已了解不少。

9 manifestation   

n.表现形式；表明；现象

参考例句：

• Her smile is a manifestation of joy.她的微笑是她快乐的表现。
• What we call mass is only another manifestation of energy.我们称之为质量的东西只是能量的另一种表现形态。

10 tally   

n.计数器，记分，一致，测量；vt.计算，记录，使一致；vi.计算，记分，一致

参考例句：

• Don't forget to keep a careful tally of what you spend.别忘了仔细记下你的开支账目。
• The facts mentioned in the report tally to every detail.报告中所提到的事实都丝毫不差。

11 lesser   

adj.次要的，较小的；adv.较小地，较少地

参考例句：

• Kept some of the lesser players out.不让那些次要的球员参加联赛。
• She has also been affected,but to a lesser degree.她也受到波及，但程度较轻。

12 deficit   

n.亏空，亏损；赤字，逆差

参考例句：

• The directors have reported a deficit of 2.5 million dollars.董事们报告赤字为250万美元。
• We have a great deficit this year.我们今年有很大亏损。

13 diagnosis   

n.诊断，诊断结果，调查分析，判断

参考例句：

• His symptoms gave no obvious pointer to a possible diagnosis.他的症状无法作出明确的诊断。
• The engineer made a complete diagnosis of the bridge's collapse.工程师对桥的倒塌做一次彻底的调查分析。

14 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

15 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

16 neural   

adj.神经的，神经系统的

参考例句：

• The neural network can preferably solve the non- linear problem.利用神经网络建模可以较好地解决非线性问题。
• The information transmission in neural system depends on neurotransmitters.信息传递的神经途径有赖于神经递质。

17 variants   

n.变体( variant的名词复数 )；变种；变型；（词等的）变体

参考例句：

• Those variants will be preserved in the'struggle for existence". 这些变异将在“生存竞争”中被保留下来。 来自辞典例句
• Like organisms, viruses have variants, generally called strains. 与其他生物一样，病毒也有变种，一般称之为株系。 来自辞典例句

18 chromosome   

n.染色体

参考例句：

• Chromosome material with exhibits of such behaviour is called heterochromatin.表现这种现象的染色体物质叫做异染色质。
• A segment of the chromosome may become lost,resulting in a deletion.染色体的一个片段可能会丢失，结果产生染色体的缺失。

19 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

20 alterations   

n.改动( alteration的名词复数 )；更改；变化；改变

参考例句：

• Any alterations should be written in neatly to the left side. 改动部分应书写清晰，插在正文的左侧。 来自《简明英汉词典》
• Gene mutations are alterations in the DNA code. 基因突变是指DNA 密码的改变。 来自《简明英汉词典》

21 physiology   

n.生理学，生理机能

参考例句：

• He bought a book about physiology.他买了一本生理学方面的书。
• He was awarded the Nobel Prize for achievements in physiology.他因生理学方面的建树而被授予诺贝尔奖。

22 interpretation   

n.解释，说明，描述；艺术处理

参考例句：

• His statement admits of one interpretation only.他的话只有一种解释。
• Analysis and interpretation is a very personal thing.分析与说明是个很主观的事情。

23 confirmation   

n.证实，确认，批准

参考例句：

• We are waiting for confirmation of the news.我们正在等待证实那个消息。
• We need confirmation in writing before we can send your order out.给你们发送订购的货物之前，我们需要书面确认。

24 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

25 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

26 susceptible   

adj.过敏的，敏感的；易动感情的，易受感动的

参考例句：

• Children are more susceptible than adults.孩子比成人易受感动。
• We are all susceptible to advertising.我们都易受广告的影响。

27 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

28 opaque   

adj.不透光的；不反光的，不传导的；晦涩的

参考例句：

• The windows are of opaque glass.这些窗户装着不透明玻璃。
• Their intentions remained opaque.他们的意图仍然令人费解。