Familial Alzheimer's disease in two kindreds of the same geographic and ethnic origin. A clinical and genetic study.

Alzheimer's disease (AD) occurred in 37 individuals from two kindreds of Jewish ancestry with a mode of transmission suggesting an autosomal dominant genetic trait. Both kindreds originated from Byelorussia and spoke the Lithuanian dialect of Yiddish. In one of the two families one case of pathologically confirmed AD occurred with clinical and neuropathological signs of Parkinson's disease. In the other family one case of amyotrophic lateral sclerosis and one case of Down's syndrome occurred, both without clinical or pathological signs of AD. In the single kindred tested, a study of the chromosome 6 markers HLA, Bf and GLO failed to reveal a correlation between the transmission of AD and the segregation of these markers. The association of increased aneuploidy of peripheral blood chromosomes with AD was not confirmed in either of these families. Genetic differences between the familial and the sporadic form of AD are discussed.