Mitochondrial transcription factor A (TFAM) polymorphisms and risk of late-onset Alzheimer's disease in Han Chinese

Chronic mitochondria DNA (mtDNA) damage and mitochondrial dysfunction induced by increased reactive oxygen species (ROS) have been proved to contribute to the development of Alzheimer's disease (AD). Mitochondrial transcription factor A (TFAM) plays an important role in the maintenance of mtDNA integrity. Recently, some studies suggested two single nucleotide polymorphisms (SNPs) (rs1937 and rs2306604) in the TFAM gene are associated with sporadic late-onset AD (LOAD) in Caucasians. To explore the correlation between TFAM gene and LOAD, we performed a case-control study in a large Chinese cohort consisting of 394 patients and 390 healthy controls. The results showed that there were significant differences in genotype (P=0.03) and allele (P=0.04) frequencies of the SNP rs1937 between LOAD patients and controls. The minor C allele of rs1937 acted as a moderate protective factor of LOAD (P=0.04, odds ratios/OR=0.76). The logistic regression analysis also suggested an association of LOAD with SNP rs1937 (dominant model: P=0.03, OR=0.71; recessive model: P=0.02, OR=0.25; additive model: P=0.01, OR=0.68). No significant association was observed between rs2306604 and LOAD. Haplotype analysis identified the haplotype CC as a protective factor of LOAD (P=0.038, OR=0.76). This study provides the evidence that variations in TFAM are involved in the pathogenesis of sporadic LOAD in the Han Chinese population.