Polymorphism of alpha-estrogen receptor and aryl hydrocarbon receptor genes in dementia patients in Shanghai suburb

Abstract

Aim: To explore the possible association of different polymorphic forms of human alpha-estrogen receptor (ER-alpha) and aryl hydrocarbon receptor gene (Ahr) with the risk to senile dementia in farmers in Shanghai suburb.

Methods: Senile dementia patients (n=52) were examined for ER-alpha and Ahr gene polymorphism genotyping. Healthy individuals (n=125) in the same area were selected as a community control group. Two polymorphic loci, Pvu II locus and Xba I locus, of human ER- a gene were investigated by a PCR-RFLP-based procedure. The population frequencies of two polymorphic loci in exon 10 of Ahr gene, G1721A (R554K) and G1768A (V570I) were compared between patients and healthy controls using an allele-specific PCR (AS-PCR) procedure.

Results: The mutant allele frequencies of ER-alpha gene in the AD group were significantly higher than those in the control group (P=0.023, OR=2.94, 95 % CI 1.13-7.71 for Pvu II locus; P=0.046, OR=2.28, 95 % CI 1.003-5.17 for Xba I locus). The mutant allele frequencies among female AD patients were higher than those in the female controls (P=0.016, OR=3.68, 95 % CI 1.22-11.08 for Pvu II locus, P=0.029, OR=2.95, 95 % CI 1.10-7.94 for Xba I locus). The mutant form, neither in the homozygous, nor in the heterozygous form was detected at the locus of Ahr G1768A in a normal local population. No significant difference of Ahr genotype frequency at locus G1721A was noticed between the patients and healthy individuals.

Conclusion: The distribution of ER polymorphisms was significantly different between Chinese and some other ethnic populations. The results suggested that ER-alpha gene polymorphisms might be related to the individual susceptibility to AD, especially in the females. However, it did not support the association of Ahr gene polymorphism with higher risk of senile dementia.