小儿脊髓性肌肉萎缩症,简称脊肌萎缩症(spinal mus-cular atrophy,SMA),是由于脊髓前角细胞变性导致的以进行性肌无力、肌萎缩为特征的常染色体隐性遗传病。其发病率在活产婴中为1/10000,人群中携带者频率约为1/50。本病居致死性常染色体隐性遗传病的第2位,仅次于囊性纤维变性? Pediatric spinal muscular atrophy, referred to as spinal muscular atrophy (SMA), is an autosomal recessive disorder characterized by progressive muscle weakness and muscle atrophy due to degeneration of the spinal cord anterior horn cells. Its incidence in live births is 1/10000, the frequency of carriers in the population is about 1/50. This disease is fatal autosomal recessive genetic disease No. 2, second only to cystic fibrosis?