Emery A E
Medical School, University of Edinburgh, Scotland.
Prog Clin Biol Res. 1989;306:15-28.
X-linked DMD is a serious condition characterized by progressive muscle wasting and weakness and death ensues in the late teens or early twenties. There is considerable clinical variability even within families and some suggestions of genetic heterogeneity. Though skeletal muscle is primarily involved, other tissues are also affected including cardiac and smooth muscle. Other abnormalities include mental retardation, thymus hyperplasia and possibly certain endocrinological changes. The responsible locus is at Xp21 and the gene product is a very large protein (dystrophin) which is normally localised to muscle cell membranes. It is hypothesised that its absence in DMD may result in instability of the muscle cell membrane with resultant ingress of calcium, an increase in intracellular calcium, and cell death. An understanding of this pathway is important in devising an effective treatment.
X连锁型杜氏肌营养不良症是一种严重病症，其特征为进行性肌肉萎缩和无力，患者多在十几岁后期或二十岁出头死亡。即使在同一家族中，临床症状也存在很大差异，这提示存在基因异质性。虽然主要受累的是骨骼肌，但其他组织也会受到影响，包括心肌和平滑肌。其他异常情况包括智力迟钝、胸腺增生以及可能的某些内分泌变化。致病基因位点位于Xp21，基因产物是一种非常大的蛋白质（抗肌萎缩蛋白），正常情况下定位于肌肉细胞膜。据推测，杜氏肌营养不良症患者体内缺乏该蛋白可能导致肌肉细胞膜不稳定，进而使钙内流，细胞内钙含量增加，最终导致细胞死亡。了解这一途径对于设计有效的治疗方法很重要。
