Single nucleotide polymorphism in DNMT3B promoter and the risk for idiopathic thrombocytopenic purpura in Chinese population.

OBJECTIVE: Epigenetic changes in gene expression, including DNA methylation and histone modifications, might contribute to autoimmunity. DNA methylation is mediated by a family of DNA methyltransferases. Polymorphisms of the DNA methyltransferase 3B (DNMT3B) gene may influence DNMT3B activity on DNA methylation, thereby modulating the susceptibility to some diseases. The purpose of this study was to investigate the association between the single nucleotide polymorphism (SNP) in promoter of the DNMT3B gene and the risk for development of idiopathic thrombocytopenic purpura (ITP).

METHODS: In this hospital-based case-control study, the DNMT3B SNP was genotyped in 201 patients with ITP and 136 healthy controls by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS: The C/C genotype was not detected in both the patients with ITP and the controls. In the controls, the frequencies of T/T and C/T genotypes and T and C alleles were 97.8%, 2.2%, 98.9%, and 1.1%, respectively. There was no significant difference in genotype and allele distribution between the patients with ITP and the controls (P = 0.745 and 0.747, respectively). No significant difference was observed in genotype and allele distribution between the two groups when stratified by the age. The similar results were shown among the four groups of patients with ITP: acute childhood, chronic childhood, acute adult, and chronic adult.

CONCLUSION: This polymorphism was distributed similarly between the patients with ITP and the controls. It demonstrated that it may not be used as a stratification marker to predict the susceptibility to ITP, at least in the population of North China.