themolecularbasisofmusculardystrophy

themolecularbasisofmusculardystrophy内容摘要：

truncated（删节的） but mostly functional dystrophin is produced. In these BMD patients, the extent and progression of the muscle weakness is less severe. 如果基因的突变没有完全打乱 “三子一窝”的基因阅读框， 也就说基因字母（核酣酸）缺 失或增加的数量能被 3整除， 没有余数。 这种情况下抗肌萎 缩蛋白被缩短或者拉长，同时 基因的改变发生在非关键区 域，例如抗肌萎缩蛋白的中 段，使得抗肌萎缩蛋白仍然能 发挥部分的功能，这就形成了 良性的假肥大型进行性肌营养 不良。 BMD 假如抗肌萎缩蛋白的基因突变 完全打乱了基因阅读框，也就 是缺失或增加的核酣酸数量不 能被 3整除，那么从基因突变的 位点直到抗肌萎缩蛋白的终 点，所有合成的氨基酸都是错 误的，那么不完全的抗肌萎缩 蛋白无法发挥它的正常功能， 这样就形成了杜氏进行性肌营 养不良。 inframe out of frame DMD The parison between Becker and Duchenne Normal dystrophin Staining around the rim of muscle fibers Absent dystrophin No staining around the rim of any muscle fibers Duchenne Muscular Dystrophy: Dystrophin staining（染色） Western blot of dystrophin Lane 1: Becker dystrophy。 Dystrophin has reduced abundance but normal size. Lane 2: Becker dystrophy。 Dystrophin has reduced size and abundance. Lane 3: Normal。 Dystrophin has normal size and amount. Lane 4: Duchenne dystrophy。 Almost no protein is present. Lane 5: Duchenne dystrophy。 Dystrophin has severely reduced abundance. Normal BMD DMD DMD amp。 BMD • BMD is a less severe form ,in which the same protein dystrophin is present but is abnormal or greatly reduced in amount . • An arbitary means of distinguishing the two disorders depends on whether the affected person can still walk at age 16 years. Duchenne muscular dystrophy is the most mon form of MD and primarily affects boys. Onset is between 3 and 5 years and the disorder progresses rapidly. Most boys are unable to walk by age 12. DMD occurs in about 1 in 3,500 male births, and affects approximately 8,000 boys and young men in the United States. Symptoms症状 WHAT HAPPENS TO THE VOLUNTARY MUSCLES OF SOMEONE WITH DMD ? Difficulty walking, such as being late in learning how to walk (more than 18 months old), having a waddling gait or walking on toes or balls of the feet. • Difficulty running or jumping caus。