Of them the most serious is Duchenne type. Those with this strain usually come down with the disease before the age of five, lose the ability to walk within ten years, and die from heart disease and respiratory infection before the age of 20.
其中要以「裘馨型」（Duchenne）最嚴重，這一型患者多在五歲前就發病，發病十年內就不能步行，大部分在二十歲以前會因心臟衰竭、呼吸道感染而死亡。