An association between cognitive performance in elderly people and variability in the codon 129 of the prion protein gene (PRNP) has been recently described. The authors analyzed this polymorphism in 278 sporadic AD patients and 268 cognitively normal control subjects. Analyses stratifying by APOE genotype, age, and gender failed to reveal any association between homozygosity for the 129 PRNP methionine or valine alleles and AD.

Interleukin (IL)-1 is a potent proinflammatory cytokine that is markedly overexpressed in the brains of patients with Alzheimer's disease (AD). The IL-1A [-889] allele 2 has been shown to increase AD risk, probably by upregulating the inflammatory cascade in the disease process. A case-control study utilizing a clinically well-defined group of 298 sporadic AD patients and 306 control subjects was performed to test this association. Our data show that the IL-1A allele 2 is a risk factor in a dose-dependent manner, the risk of developing AD with two copies of the IL-1A allele 2 (odds ratio 3.1, 95 % CI 1.30-7.45) being approximately double that of one copy of the IL-1A allele 2 (odds ratio 1.4, 95 % CI 0.99-1.94, P for trend = 0.0004). Furthermore, the risk associated with the IL-1A allele 2 was not restricted to AD patients of a particular age, and we could confirm this association in our early-onset and late-onset AD patients.

No abstract

The genetics of Alzheimer’s disease (AD) is complex. Three genes (amyloid precursor protein, presenilin 1 and presenilin 2) have been described in the relatively rare, early-onset, autosomal dominant familial form of AD. In the common, non-familial (sporadic) late-onset AD, the major known genetic risk factor is the Ε4 allele of the apolipoprotein E (APOE) gene. However, at least half of the people who develop AD do not carry this allele, and not all people who do carry this allele develop AD even if they live to an old age. Therefore, approximately 30 other candidate genes involving a protein in a critical pathway in the pathogenesis of disease (principally interaction with amyloid-β, oxidative stress and inflammation/apoptosis) have been considered as risk factors for sporadic AD. Then these genes have been sequenced in search of genetic variability or polymorphisms, and each putative polymorphism has been reported to alter the risk of AD either directly or by an interaction with the APOE Ε4 allele. However, positive-association studies with these candidate genes have not been consistently confirmed.

Our study is the first to demonstrate that lower susceptibility to AD determined by the K variant of BCHE is dependent on gender.