Geographical distribution of amyotrophic lateral sclerosis with neurofibrillary tangles in the Kii peninsula of Japan

Between 1984 and 1996 we histopathologically examined 26 autopsy cases of a myotrophic lateral sclerosis (ALS) from the Mie Prefecture in eastern and s outhern Kii Peninsula, which includes the Hohara ALS focus. Four of the ind ividuals had a moderate number of neurofibrillary tangles in the locus coer uleus, substantia nigra, raphe nucleus, periaqueductal grey and hippocampus in addition to the histological changes of ALS. All four came from the vic inity of Hohara; symptoms of ALS developed in 1979, 1987, 1991 and 1993, Tw o had family history of ALS, and one, of parkinsonism-dementia. These findi ngs confirm that Kii type ALS occurs continuously in and near the Hohara fo cus.