Polymorphisms of PICALM gene in Alzheimer's disease risk: a meta-analysis

Alzheimer's disease (AD) is the most common type of dementia. Recent genome-wide association studies have identified that PICALM is one of the numerous reproducible AD-associated risk genes, and variants in PICALMare shown to be involved in this disease. However, the results remain conflicting. In this meta-analysis, we searched the online electronic database to retrieve related articles concerning the role of PICALM polymorphisms in AD risk and to systematic reevaluate the exact association. Overall, we screened out ten case-control studies, including 6866 AD patients and 13205 controls. Our results found that A allele of rs3851179 (A vs. G: OR=0.84, 95% CI=0.75-0.94, P=0.002) and C allele of rs541458 (C vs. T: OR=0.85, 95% CI=0.74-0.97, P=0.02) were associated with AD incidence. This significant relationship was also found in GA+AA and AA genotypes of rs3851179, and CC+TC genotype of rs541458 variants (P< 0.05). Subgroup analysis by ethnicity showed that rs3851179 variant was genetic factor for AD in Caucasians, while only A allele was associated in Asians; C allele and CC+TC genotype of rs541458 in Caucasians, while no association was found in Asians. For Chinese population, neither these variants was associated with AD risk. In conclusion, our results found that rs3851179 and rs541458 were associated with AD risk. However, more data about other ethnicities with large crowds were needed in the future studies.