THE GENOTYPE-2 2 OF THE PRESENILIN-1 POLYMORPHISM IS DECREASED IN SPANISH EARLY-ONSET ALZHEIMERS-DISEASE/

We have found a significantly lower frequency of the presenilin-1 (PS- 1) intronic polymorphism 2/2 genotype in early-onset Alzheimer's disea se (AD) patients without APOE epsilon 4 alleles (2/2 = 0.054; P = 0.00 9) as compared to age matched non-epsilon 4 controls (2/2 = 0.227). Mo reover the average age of onset in AD patients with the PS-1 2/2 genot ype is older than that in AD patients with a 1/2 genotype or with a 1/ 1 genotype. This data suggest a protective effect of the 2/2 genotype which would delay the age of onset in AD. Our results do not support a n association between the 1/1 genotype and AD. However, a non-signific ant increase of the 1/1 genotype is found in non-epsilon 4 AD patients (P = 0.20). (C) 1997 Elsevier Science Ireland Ltd.