Absence of a close linkage between Alzheimer's disease susceptibility gene and a polymorphic DNA probe coding for beta-amyloid.

The hypothesis of a connection between Alzheimer's disease (AD) gene and the probe coding for beta-amyloid (beta-A), located on chromosome 21, was investigated in a large study group from Calabria, in which AD was transmitted as an autosomal dominant Mendelian trait. Segregation analysis of one EcoRI restriction polymorphism of beta-A, after molecular hybridization with a long cDNA probe of DNAs from key-individuals in the study group, determined that there was not a close connection between AD and beta-A.