Juvenile muscular atrophy of the distal upper limb (Hirayama disease) associated with atopy

Juvenile muscular atrophy of the distal upper Limb (Hirayama disease) is a rare disease predominantly affecting the anterior horn cells of the cervica l spinal cord in young men. Although the disease is considered to be a type of cervical myelopathy, the mechanism remains unknown. An immunological st udy of five consecutive patients with this disorder who were examined in th e neurology clinic at Kyushu University Hospital during the past 2 years we re performed. Ah developed distal muscular atrophy and weakness of one or b oth upper limbs in the second decade, and showed forward displacement of th e dural sac and passive dilatation of the posterior venus plexus at the low er cervical portion on MRI during neck flexion. Four of the five patients h ad one or more coexistent airway allergies, such as allergic rhinitis, poll inosis, and asthma, and all five patients had a family history of atopic or allergic disorders in close relatives. Four of the five patients had mild eosinophilia. All five patients commonly had IgE specific to two mite antig ens, Dermatophagoides pteronyssinus and Dermatophagoides farinae, whereas t hree of them also showed a raised total serum IgE concentration. The freque ncy of mite antigen specific IgE was significantly higher in the present pa tients with Hirayama disease than in 82 healthy controls (26/82, p <0.005). These findings suggest that atopy may be one of the contributing factors f or Hirayama disease.