Association between HLA-A Alleles and Alzheimer’s Disease in a Southern Chinese Community

BACKGROUND/AIM: HLA-A is a locus of the major histocompatibility complex situated on chromosome 6p21.3. Several genome-wide linkage analyses suggested that a putative locus predisposition for Alzheimer's disease (AD) is found on chromosome 6p21. In this study, we investigated the association between HLA-A alleles and AD in a Chinese community. METHODS: Fine genotyping of 160 Chinese AD and 167 age-matched nondemented subjects was performed for the first time by sequence-based typing of the HLA-A locus. RESULTS: We found that HLA-A2 carriers (including prevalent alleles, 0201, 0203 and 0207) were more prevalent in the AD group; the frequency of HLA-A2 was increased in AD patients versus controls, but the difference was not significant after Bonferroni correction for the number of alleles tested (p = 0.075). A gene-gene interaction was observed between ApoE and HLA-A, the presence of HLA-A24 (particularly the prevalent allele 2402) might act as another independent risk factor of developing AD for subjects not carrying the ApoE epsilon4 allele (relative risk = 2.98, 95% CI = 1.14-8.24). Carriers of HLA-A2 had an earlier onset of AD by 2.4 years (p = 0.030) and HLA-A2 interacted with ApoE epsilon4 in modulating the age at onset in AD. CONCLUSIONS: This study suggested that HLA-A may be involved in the pathogenesis of AD.