时差N小时 什么是儿童早衰症?(上)（在线收听）

Progeria was first described in the nineteenth century. The mysterious disease is often thought of as premature 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 arteries 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 genetic point mutation.

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 genes are being copied to make egg or sperm, just one position in one DNA strand 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 gene that encodes lamin A, a protein in the cell’s nucleus, 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。