Genetic and clinical studies of Japanese patients with familial amyloid polyneuropathy.

We examined the DNA analysis of familial amyloid polyneuropathy (FAP) patients and their families from Nagano and Hiroshima prefectures in Japan using recombinant DNA techniques and compared the results with the clinical features. This study indicated that the valine-methionine change prealbumin gene was closely related to the clinical features of type 1 FAP. The DNA analysis was valuable for the definite diagnosis of type 1 FAP even in sporadic and asymptomatic cases. FAP patients from Iiyama city and Ogawa village area in the Nagano prefecture had the same mutation despite differences in clinical features. The onset of the sporadic FAP cases was later than that of the FAP patients who had family histories.