The presenilin 1 p.Gly206Ala mutation is a frequent cause of early-onset Alzheimer's disease in Hispanics in Florida.

Mutations in the gene encoding the presenilin-1 protein (PSEN1) were first discovered to cause Alzheimer's disease (AD) 20 years ago. Since then more than 200 different pathogenic mutations have been reported, including a p.Gly206Ala founder mutation in the Hispanic population. Here we report mutation analysis of known AD genes in a cohort of 27 early-onset (age of onset ≤65, age of death ≤70) Hispanic patients ascertained in Florida. The PSEN1 p.Gly206Ala mutation was identified in 13 out of 27 patients (48.1%), emphasizing the importance of this specific mutation in the etiology of early-onset AD in this population. One other patient carried the known PSEN1 p.Gly378Val mutation. Genotyping of the PSEN1 p.Gly206Ala and p.Gly378Val mutations in 63 late-onset Hispanic AD patients did not identify additional mutation carriers. All p.Gly206Ala mutation carriers shared rare alleles at two microsatellite markers flanking PSEN1 supporting a common founder. This study confirms the p.Gly206Ala variant as a frequent cause of early onset AD in the Hispanic population and for the first time reports the high frequency of this mutation in Hispanics in Florida.