X-linked spinal and bulbar muscular atrophy of late onset. A separate type of motor neuron disease?

The clinical, electrophysiological and muscle biopsy findings of 7 cases with a peculiar form of X-linked hereditary degenerative motor neuron disease are presented. It is suggested that the disease might be a separate clinical entity with the following characteristics: (1) sex-linked recessive inheritance, (2) unusual but not invariable late onset, (3) slow progression, (4) facial-bulbar and proximal spinal muscle involvement, (5) consistent fasciculations, sometimes massive and more pronounced about the lips, chin and tongue, (6) fine tremor of the hands, (7) muscle cramps usually preceding the other symptoms, and (8) gynaecomastia as a frequent but not a constant feature.