[Familial distal progressive spinal amyotrophy with asymmetry of the lower limbs].

Two cases of spinal muscular atrophy, localized on the lower limbs and strictly unilateral, in two half brothers, are reported. Such a distribution of clinical changes and such a hereditary transmission appear to be unusual in hereditary motor-neuronopathies. A recessive heterotopic transmission may be suspected. To our knowledge, it has been reported in Kennedy's disease only.