Background: DNA methylation is an epigenetic process that refers to chromatin-based mechanisms in the regulation of gene expression without DNA alternation. It is mediated by DNA methyltransferases (DNMTs). The DNA methyltransferase 3B (DNMT3B) gene contains a C-to-T single nucleotide polymorphism (SNP; rs2424913) in the Promotor region, 149 base pairs from the transcription start site, which is reported to significantly increase the Promotor activity.

Objective: To investigate the prevalance of rs2424913 single nucleotide polymorphism located in the DNMT3B gene Promotor.

Methods: In the present study, we investigated the prevalence of rs2424913 single nucleotide polymorphism located in DNMT3B gene Promotor by restriction fragment length polymorphism (PCR-RFLP) in Egyptian pediatric chronic immune thrombocytopenia (ITP) patients and controls.

Results: The homozygous genotype (TT) was significantly higher in our patient and conferred almost 3-fold increased risk of chronic ITP when compared to controls.

Conclusions: The present study shows that DNMT3B rs2424913 promotor polymorphism represents a genetic risk factor that may play an important role in understanding the pathogenesis of chronic ITP.