Hereditary myoclonus and progressive distal muscular atrophy.
Myoclonus occurs in a variety of pathological conditions, some inherited. We recently evaluated 3 members of a Louisiana-Texas family with an autosomal dominant disorder manifested by adult-onset, generalized, stimulus-sensitive myoclonus and slowly progressive distal muscle weakness and wasting. The analyses of cerebrospinal fluid homovanillic acid and 5-hydroxyindoleacetic acid before and after probenecid provided some evidence of impaired turnover of central dopamine and serotonin. Treatment with clonazepam resulted in complete and lasting improvement of the myoclonus. A postmortem examination in 1 member of the family revealed chiefly neuronal degeneration of the anterior horn cells, Clark's nucleus, and the lower cranial nerve nuclei. A similar syndrome has not previously been reported.
D000328:Adult; D000368:Aged; D005260:Female; D006719:Homovanillic Acid / Q000134:cerebrospinal fluid; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000134:cerebrospinal fluid; D008297:Male; D009133:Muscular Atrophy / Q000150:complications / Q000235:genetics / Q000473:pathology*; D009207:Myoclonus / Q000150:complications / Q000235:genetics / Q000473:pathology*
D006897:Hydroxyindoleacetic Acid; D006719:Homovanillic Acid