Single Nucleotide Polymorphism in DNMT3B Promoter and the Risk for Idiopathic Thrombocytopenic Purpura in Chinese Population Zhenping Chen & Zeping Zhou & Xiaoli Chen & Jianhui Xu & Aijuan Liu & Weiting Du & Dongsheng Gu & Jing Ge & Zhenxing Guo & Xiaoyan Wang & Xunwei Dong & Qian Ren & Renchi Yang Received: 18 December 2007 / Accepted: 11 March 2008 / Published online: 25 April 2008 # Springer Science + Business Media, LLC 2008 Abstract Objective Epigenetic changes in gene expression, including DNA methylation and histone modifications, might con- tribute 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 modulat- ing 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. Keywords DNA Methyltransferase 3B . idiopathic thrombocytopenic purpura . polymorphism Introduction Immune thrombocytopenic purpura (ITP) is an acquired organ-specific autoimmune disease with the destruction of autoantibody-mediated platelet and the reduction of platelet production [1–3]. The etiology of ITP remains unclear, but it is generally accepted that both environmental and genetic factors and probably also a synergistic relationship between these factors play important roles in the development of the disease. Interactions between environmental and genetic factors are proposed to explain why autoimmunity afflicts certain individuals but not others [4]. The environmental factors can modify the susceptibility to this disease, in part, through modulating and inducing some epigenetic changes. In recent years, epigenetics has become an exciting and evolving field of research, and the roles in autoimmune disease were extensively discussed [4–6]. DNA methylation is a key epigenetic modification of the genome. In mammals, the methylation, occurring at position 5 of the cytosine residues in the CG pairs, could regulate gene expression by changing chromatin structure. J Clin Immunol (2008) 28:399–404 DOI 10.1007/s10875-008-9198-z Z. Chen : Z. Zhou : X. Chen : J. Xu : A. Liu : W. Du : D. Gu : J. Ge : Z. Guo : X. Wang : X. Dong : Q. Ren : R. Yang (*) State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 288 Nanjing Road, Tianjin 300020, People’ s Republic of China e-mail: rcyang65@yahoo.com