Familial amyloid polyneuropathy (Finnish type) in a Japanese family: Clinical features and immunocytochemical studies.

Familial amyloid polyneuropathy (FAP: type IV), known as familial amyloidosis of the Finnish type (FAF), is very rare and reported only in a few countries. The gelsolin mutation G654A is most frequent causative gene in FAF family. The clinical phenotype of FAF possesses several neurological characteristics with multiple cranial nerve signs, in addition to a peculiar exanthema of "lichen amyloidosus" and pendulous skin "cutis laxa", and the carpal tunnel syndrome. We report a new Japanese FAF family presenting bilateral atrophies and fasciculations of the facial muscles and tongue. The patients in our family presented with skin changes as "lichen amyloidosus" and "cutis laxa". In this FAF family, lichen amyloidosus appeared under sunlight and high temperatures in the summer season every year. Two patients in our family presented with common clinical features of FAF, except for the above laboratory results. Including previous cases and our family, this clinical phenotype is similar to the gelsolin gene mutation (G654A) in FAF family members.