Polycystic ovary syndrome is one of the most frequently encountered endocrine malfunctions. Methylenetetrahydrofolate reductase (MTHFR) plays a vital role in folate metabolism, DNA methylation, and RNA synthesis. We carried out a study to investigate the association between MTHFR C677T and A1298C genetic variations and the risk of polycystic ovary syndrome in a Chinese population. We recruited 244 patients and 257 control subjects from an Inner Mongolian Medical University to this hospital-based, case-control study. The genotyping of the MTHFR C677T and A1298C polymorphisms was carried out using polymerase chain reaction coupled with restriction fragment length polymorphism. Using multiple logistic regression analysis, we found that the TT genotype and the T allele of MTHFR C677T carriers showed increased risk of polycystic ovary syndrome compared with the wild-type genotype or allele carriers. The adjusted ORs for the TT genotype and the T allele of MTHFR C677T were 1.84 (1.05-3.26) and 1.38 (1.06-1.81), respectively. Subjects carrying the CC genotype (OR = 3.98, 95%CI = 1.60-11.23) and the C allele (OR = 1.46, 95%CI = 1.07-2.00) of MTHFR A1298C had an elevated risk of polycystic ovary syndrome compared with the AA genotype and A allele carriers. In conclusion, our study suggests that the MTHFR C677T and A1298C polymorphisms may have contributed to the risk of polycystic ovary syndrome in the Chinese women investigated. Further research involving a greater number of individuals is warranted to confirm our results.

The X-ray repair cross-complementation group 1 (XRCC1) protein plays an important role in base excision repair, and the genetic polymorphisms in the XRCC1 gene influence its function. XRCC1 codon 280 polymorphism is an Arg-His change in the XRCC1 gene. Many studies were published to investigate the association between XRCC1 codon 280 polymorphism and risk of lung cancer, but the results were inconsistent. We performed a meta-analysis of 16 studies with a total of 18,660 subjects (8,736 cases and 9,924 controls). The pooled odds ratios (OR) and corresponding 95 % confidence intervals (95 % CI) for the gene-disease association were calculated. Overall, there was a significant association between XRCC1 codon 280 polymorphism and increased risk of lung cancer (HisHis vs. ArgArg: OR = 1.53, 95 % CI 1.08-2.16, P = 0.016; HisHis vs. ArgArg/ArgHis: OR = 1.55, 95 % CI 1.10-2.19, P = 0.012). However, subgroup analysis by race failed to confirm the obvious association in Europeans and Asians. Therefore, there is a significant association between XRCC1 codon 280 polymorphism and increased risk of lung cancer. More studies with a large sample are needed to further evaluate the possible race-specific effect in the association above.