[Familial amyloidotic polyneuropathy type IV (Finnish type)--the first description of a large kindred in Japan].

Familial amyloidotic polyneuropathy type IV, one of the hereditary systemic amyloidoses with an autosomal dominant trait, is clinically characterized by cranial neuropathy and corneal lattice dystrophy. Recent biochemical studies have indicated that the amyloid fibril protein in FAP IV is related to gelsolin, an actin-modulating protein. Cases were clustered in the Finnish population and only a few cases have been reported from other populations. Here we described a large kindred with FAP IV as the first report in Japan. This family comprises 42 members in three generations with 14 affected individuals. We examined 7 patients at the age ranging from 43 to 80 years. All cases have corneal lattice dystrophy type II. The disease begins with slowly progressive facial weakness in the fifth or sixth decade of life and consequently the V, XII, IX and X cranial nerves become involved. Peripheral neuropathy of the extremities remained mild until late of life. Microscopy of skin biopsy samples showed deposits of amyloid around the eccrine glands, sebaceous glands, epidermal-dermal junction and blood vessel walls. Immunohistochemistry of the skin revealed the immunopositive material against a monoclonal antibody to gelsolin in the amyloid deposits. Molecular analysis of the gelsolin gene is now in progress.