Gutartige distale Muskelatrophie Typ Hirayama

Benign distal myatrophy type Hirayama is a rare disease. Clinical characteristics are sporadic manifestation in young males between 15 and 25 years of age, insiduous begin and slow progression over 1 to 5 years, usually unilateral expression (95 %), atrophy and weakness of hand and arm muscles forming a bottle neck-shaped distal lower arm, and cold paresis of the involved muscles (80 %). EMG and muscle biopsy show chronic neurogenic changes of the muscles and neuropathology a loss of anterior horn cells. The existence of the syndrome is established worldwide. However, the disease entity is still under discussion. A definite genetic abnormality has not been discovered so far. The variability of symptoms and signs is also controversial. Single reports describe familial occurrence and localisation at the legs.