Without the support of dystrophin in place, the sarcolemma essentially wilts and becomes unstable.

没有肌萎蛋白的支撑，肌膜塌变得不稳定。

Okay, so as a quick recap: the protein dystrophin is super important for stabilizing the muscle cell membrane.

肌萎蛋白对肌纤维稳定性的维持极其重要。

Alright, so the dystrophin gene is a huge gene on the X-chromosome, that has 79 exons and is over 2 million base pairs in length.

肌萎蛋白基因是X染色体上个庞大的基因，含有79个外显子，全长超过2000kbp（书上通为bp，碱基对）。

Now, the fact that both Duchenne and Becker muscular dystrophy result from mutations in the same dystrophin gene means that they are " allelic disorders, "

DMD和BMD都是由于肌萎蛋白基因突变引起的，意味着二者是“等位基因疾病”。

Within that group, dystrophinopathies are the most common, which includes Duchenne muscular dystrophy, or DMD, and Becker muscular dystrophy, both of which result from mutations in the dystrophin gene.

这些功能紊乱中，营养不良疾病是最见的，包括Duchenne型肌营养不良（DMD）和Becker型肌营养不良（BMD）；这二者都是由肌萎蛋白基因突变导致的。

In addition to those two, genetic mutations in other genes are responsible for several dozen other muscular dystrophies, some of which code for proteins that form a protein complex with dystrophin protein.

除了这两种疾病，其它基因的突变导致了其它几十种肌营养不良，其中些基因编码形成肌萎蛋白相关蛋白复合体的蛋白质。

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，可以预料到女性半的细胞中肌萎蛋白基因是正的，另半是有缺陷的，通这些人无临床症状。

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，而正基因更少，这类人群就是“显性携带者”，意味着他们也会有部分症状表现。

Later symptoms include needing a wheelchair because of severe weakness, developing respiratory failure because of a weak diaphragm, scoliosis, and developing dilated cardiomyopathy and arrhythmias since the dystrophin protein is also expressed in heart muscle.

后期症状包括，由于严重的肌无力需坐轮椅，由于膈肌无力会发生呼吸衰竭、脊柱侧凸，因为肌萎蛋白也表达于心肌纤维，还会引发扩张型心肌病和心律失。