[Hereditary motor neuron disease: the proximal, adult, sex-linked form (or Kennedy disease). Clinical and neuroendocrinologic observations].

Clinical, electrophysiological, histological and neuroendocrinological findings in a peculiar form of progressive spinal and bulbar muscular atrophy affecting 4 members in two different families are reported. The clinical hallmarks, which characterize this entity among the group of degenerative motor neuron diseases are: sex-linked recessive inheritance; onset in the third decade; slow progression; involvement of facial and bulbar muscles in addition to wasting of the proximal and, in some cases, the distal musculature; asymmetry of clinical signs; consistent and abundant fasciculations predominantly in the peri-oral muscles; intention tremor and a well-developed gynaecomastia, which is the first clinical sign. Electrophysiological and histological findings confirm the neurogenic origin of the muscular atrophy; in addition, muscle biopsy shows "myopathic-like" changes in one case and serum muscle enzyme levels are elevated in all neurologically affected patients. It is believed that the clinical entity corresponds to the rare type III proximal hereditary motor neuropathy (or "Kennedy's disease"), of which 25 published cases are reviewed. Neuroendocrinological data in two patients demonstrate an androgenic insufficiency of hypothalamo-hypophyseal origin and high levels of circulating oestrogens, which probably have induced gynaecomastia. Dynamic neuroendocrinological tests suggest that lesions of certain hypothalamic nuclei may exist, which should be looked for in the forthcoming anatomical studies.