时差N小时 什么是儿童早衰症?(上)

Progeria was first described in the nineteenth century. The mysterious disease is often thought of as premature¹ aging.

儿童早衰症的最早记载是在19世纪。这种神秘的疾病通常被认为是过早衰老。

Children with progeria are normal for their first year of life, but then develop medical problems normally seen in the elderly.

患有早衰症的儿童在一岁前一切正常，但之后会患上老年人才会得的疾病。

Their bones weaken. Their skin wrinkles. They lose their hair.

他们的骨骼变得脆弱，皮肤逐渐松弛，头发开始脱落。

They die from heart attacks or strokes brought on by hardened arteries² and high blood pressure. None lives past their early teens.

他们可能会死于由动脉硬化及高血压引发的心脏病或中风。没有一位患者能够活过少年早期。

In 2003, researchers discovered what causes progeria: a genetic⁴ point mutation⁵.

2003年，研究人员发现了少年早衰症的病因：基因点突变。

That means that when genes⁶ are being copied to make egg or sperm⁷, just one position in one DNA⁸ strand⁹ is copied wrong.

这是指当基因复制形成卵细胞或精子时，DNA单链上的某一处复制出现异常。

It is like copying a pancake recipe and replacing baking powder with salt. The pancake is not going to rise.

例如，你照着食谱做煎饼，却错把盐误认为发酵粉。煎饼当然无法发酵。

For children with progeria, the gene³ that encodes lamin A, a protein in the cell’s nucleus¹⁰, is faulty.

对于患有早衰症的儿童来说，其体内编码核纤层蛋白A（细胞核内的一种蛋白质）基因是有缺陷的。

1 premature   

adj.比预期时间早的；不成熟的，仓促的

参考例句：

• It is yet premature to predict the possible outcome of the dialogue.预言这次对话可能有什么结果为时尚早。
• The premature baby is doing well.那个早产的婴儿很健康。

2 arteries   

n.动脉( artery的名词复数 )；干线，要道

参考例句：

• Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。 来自《简明英汉词典》
• This is the place where the three main arteries of West London traffic met. 这就是伦敦西部三条主要交通干线的交汇处。 来自《简明英汉词典》

3 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

4 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。

5 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。

6 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

7 sperm   

n.精子，精液

参考例句：

• Only one sperm fertilises an egg.只有一个精子使卵子受精。
• In human reproduction,one female egg is usually fertilized by one sperm.在人体生殖过程中，一个精子使一个卵子受精。

8 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。

9 strand   

vt.使（船）搁浅，使（某人）困于（某地）

参考例句：

• She tucked a loose strand of hair behind her ears.她把一缕散发夹到了耳后。
• The climbers had been stranded by a storm.登山者被暴风雨困住了。

10 nucleus   

n.核，核心，原子核

参考例句：

• These young people formed the nucleus of the club.这些年轻人成了俱乐部的核心。
• These councils would form the nucleus of a future regime.这些委员会将成为一个未来政权的核心。