Plasma levels of apolipoprotein E and genetic markers in elderly patients with Alzheimer's disease

Besides, apolipoprotein E (APOE) polymorphism, whose association with Alzhe imer's disease (AD) has been confirmed in most of the numerous population s amples studied, other markers have been investigated. In most cases the ass ociation firstly described was not confirmed in subsequent works. Since it is important to examine these associations in as many populations as possib le, we investigated APOE, APOC1, APOC2, alpha-l antichymotrypsin (ACT) and presenilin-1 (PS-1) polymorphisms in a series of elderly patients with late -onset sporadic AD from Northern Italy and in a sex and age-matched control group. We could not confirm the significantly higher frequency of the ACT* A allele among carriers of APOE e*4 allele described elsewhere, although a similar trend was observed. The APOC2 and the PS-1 distributions were simil ar between patients and controls, However, we observed a significant differ ence in the genotype and allele frequencies of APOE and APOC1: patients had higher e*4 and C1*2 allele frequencies. This finding confirms the importan t role for APOE in AD occurrence. In addition, APOC1 seems to be an interes ting marker because, though in strict linkage disequilibrium with APOE, it seems to play an independent role in AD risk. In contrast to previously rep orted data, plasma apoE concentrations were similar in patients and in cont rols. An interaction between APOE and APOC1 polymorphisms and apoE levels w as observed in patients: subjects carrying the APOE E3/E2 or the APOC1 2-2 genotype have higher apoE concentrations than those who do not. (C) 1999 El sevier Science Ireland Ltd. All rights reserved.