Two deoxyribonuclease I gene polymorphisms and correlation between genotype and its activity in Japanese population

Deoxyribonuclease I (DNase I) plays important roles for DNA fragmentation and degradation during programmed cell death. The single nucleotide polymorphism (SNP) at DNase I, designated as DNASE1, in exon 8 (A2317G) is considered to be one of the susceptibility genes for gastric and colorectal carcinoma and myocardial infarction. Recent research has shown the presence of a novel 56-bp variable number of tandem repeat (VNTR) polymorphism in intron 4 at DNase I, designated as HumDN1. In the present study, DNASE1 and HumDN1polymorphisms and serum DNase I activities in each different genotype were investigated in 137 Japanese populations. The allele frequencies of A and G in DNASE1 were 0.5839 and 0.4161, respectively. The allelic frequencies of alleles 2, 3, 4, and 5 in HumDN1 were 0.0219, 0.5803, 0.2226, and 0.1752, respectively. In the DNASE1 polymorphism, the activities of genotypes GG and AG were significantly higher than that of AA. As for the HumDN1 polymorphism, the activity of genotype 55 was significantly higher than the activities of 33 and 34. In addition, a significant difference was observed between haplotypes AA/33 and GG/55. The analysis of the correlation between genotype and DNase I activity may be potentially useful for clinical purposes.