The disease is caused by a defective gene.

这种疾病是由有缺陷的基因引起的。

He's got defective genes, just like you.

他基因不好 像你。

If a person has two defective alpha genes, the person has alpha thalassemia minor, which causes mild symptoms.

如果有2个α基因异常，则会出现轻度α地中海贫血，会引起轻微的症状。

We're simply adding the gene. We leave the defective gene intact. So this is what's called gene addition therapy.

我们只是加入了基因，保持有缺陷的基因不变，这就是所谓的基因添加疗法。

So how did this defective gene persist at all?

那么这个有缺陷的基因是如何持续存在的呢？

Now in my case, the defective gene I carry won't protect me against malaria.

现在就我而言，我携带的缺陷基因不会保护我免受疟疾的侵害。

Think of the enzyme produced by the defective gene as a wrong key which fits into the chemical lock of the central nervous system—but won't turn.

你可以把缺陷基因产生的酶，设想成一把错误的钥匙插在中枢神经系统的化学锁上，结果却转不开。

It's becoming a reality to correct defective genes in patients with inherited diseases, such as severe combined immunodeficiency, you may know it as the bubble boy syndrome, and sickle cell anemia.

纠正遗传性疾病患者的缺陷基因正在成为现实，例如严重的联合免疫缺陷， 你可能知道它是泡泡男孩综合症和镰状细胞性贫血。

Now if this inactivation's random, you'd expect about half of the female's cells to have a functional dystrophin gene and the other half to have a defective dystrophin gene, and these people are typically asymptomatic.

如果失活是随机的，可以预料到女性一半的细胞中抗肌萎缩蛋白基因是正常的，另一半是有缺陷的，通常这些人无临床症状。

Having said that, if more cells end up with the defective dystrophin gene, and less with the functional one, they can end up being " manifesting carriers, " meaning that they manifest or show some symptoms.

话虽如此，如果机体中有该基因缺陷的细胞更多，而正常基因更少，这一类人群就是“显性携带者”，意味着他们也会有部分症状表现。