Deoxyribonuclease I gene polymorphism in Han Chinese population: frequency and effect on glucose and lipid parameters

DNASE1, the encoding gene of deoxyribonuclease I (DNase I), exhibits polymorphisms, including a single nucleotide polymorphism (SNP A2317G) in exon 8 and a 56 bp variable number of tandem repeat, designated as HumDN1 in intron 4. Several different ethnic population studies have revealed both A2317G and HumDN1 demonstrate genetic heterogeneity in the worldwide distribution. Recently, G2317 allele was proposed as an independent risk factor for myocardial infarction in Japanese population. In the present study, we identified A2317G and HumDN1 genotypes in 402 unrelated healthy Han Chinese individuals. At the same time, the impact of different genotypes and diplotypes of DNase I on plasma lipids levels and fasting blood glucose was also illuminated. Polymerase chain reaction and restriction fragment length polymorphism were used for the detection of HumDN1 and A2317G polymorphisms. Plasma glucose and lipids were measured in fasting state by biochemical methods. Three genotypes of A2317G and 9 genotypes of HumDN1 were detected in Han Chinese population. Among them, the most predominate alleles were A2317 (frequency = 53.6%) and HumDN1*3 (frequency = 47.4%) respectively. Linkage disequilibrium between A2317G and HumDN1 polymorphisms was also observed (D' = 0.717). Haplotype A-3, presented in frequency of 46.5%, was most common. Compared to other ethnic populations, Han Chinese had its own unique DNase I gene distribution characteristics. As for the influence of DNase I gene polymorphisms on lipids and glucose levels, no association was found between either genotype or diplotype and these parameters. (all P > 0.05). Results obtained in this study could be used for anthropological investigation, probing into relations between DNase I gene and diseases.