[Sex-linked familial form of progressive spinal amyotrophy in adults].

An X-linked spinal muscular atrophy is reported in one family. Four of the five patients were examined. In three, electromyography, conduction nerve velocities and muscle biopsy were consistent with anterior horn cell disease. Similar families in the literature were reviewed and characteristic data were: 1) adult-onset, 2) proximal, bulbar and facial involvement, 3) prominent perioral fasciculations, 4) frequent association of cramps, tremor and sexual dysfunction (hypogonadism and gynecomastia), 5) very slow progression and favorable prognosis. These characteristics define, among the spinal muscular atrophies, a distinct entity named by several authors Kennedy's disease.