- spinal muscular atrophy
- spinal muscular atrophy n any of several inherited disorders (as Kugelberg-Welander disease) that are characterized by the degeneration of motor neurons in the spinal cord resulting in muscular weakness and atrophy and that in some forms (as Werdnig-Hoffmann disease) are fatal
* * *any of several hereditary, progressive, degenerative diseases of the motor cells of the spinal cord. Beginning usually in the small muscles of the hands, but in some cases (scapulohumeral type) in those of the upper arms and shoulders, the atrophy progresses to the muscles of the lower limbs. Type I is Werdnig-Hoffmann disease, the most severe type, usually fatal in infancy. Type II is an intermediate type seen in babies that is not always fatal. Type III is Kugelberg-Welander syndrome, the least severe type. Called also Aran-Duchenne disease or muscular a., Duchenne-Aran disease or muscular a., Cruveilhier a. or paralysis, and progressive spinal muscular a.
Medical dictionary. 2011.