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.

CYP1A2 polymorphism (C > A at position -163) in Ovambos, Koreans and Mongolians.

Cytochrome P450 1A2 (CYP1A2) plays an important role in metabolizing drugs and xenobiotics, and is a possible participant in the development of several human diseases. Recent studies have shown that genetic polymorphism of -163 C > A single nucleotide mutation of CYP1A2 increases the risk of myocardial infarction and modulates CYP1A2 activity. In this study, we investigated the frequency of the -163 C > A mutation in Ovambos (n = 177), Koreans (n = 250) and Mongolians (n = 153) and compared our results with other studies. Detection of this single nucleotide polymorphism was by polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP). The frequencies of mutation (CYP1A2*-163A) in the Ovambos, Koreans and Mongolians were 0.46, 0.32 and 0.21, respectively. Ovambos showed a relatively higher frequency of mutation, similar to that of Tanzanians, while the Mongolians showed the lowest frequency of all study groups, including those from previous studies. This study is the first to investigate the distribution of the CYP1A2 (-163 C > A single nucleotide polymorphism) mutant allele in Ovambo, Korean and Mongolian populations.