Background Primary immune thrombocytopenia (ITP) is a
common hematological disorder of unknown etiology. DNA
methylation is a major epigenetic modification of the DNA. It
has a golden role in gene expression. It is mediated by DNA
methyltransferases (DNMTs). The promoter of DNMT3B
gene contains some single-nucleotide polymorphisms
(SNPs) including that at position −149 (C/T), which was
suggested to be implicated in the genetic susceptibility to ITP.
The DNMT3A −448 G/A SNP in the gene promoter was found
to have a protective effect against systemic lupus
erythematosus.
Aim The aim of the study was to investigate the association
between DNMT3A −448 G/A SNP (rs1550117) and DNMT3B
−149C/T SNP (rs2424913), and the risk for primary ITP and to
evaluate the association between these SNPs and patients’
response to therapy.
Participants and methods This prospective case–control
study was conducted on 60 primary ITP patients and 30
healthy age-matched and sex-matched controls. Genotype
analysis of DNMT3A −448 G/A and DNMT3B −149C/T was
done using PCR-restriction fragment length polymorphism.
Results The frequency of the DNMT3A −448 G/A SNP variant
A-allele was significantly decreased in primary ITP patients compared with controls (odds ratio=0.829, 95%
CI=0.097–0.964). DNMT3B −149C/T SNP variant T-allele
was significantly higher in ITP patients with almost doublefold
increase in the risk of ITP in comparison to controls (odds
ratio=1.731, 95%CI=1.121–2.582).
Conclusion The DNMT3A −448 SNP variant A-allele might
has a protective effect against ITP. Also, the DNMT3B −149
SNP variant T-allele could be considered as a molecular risk
factor for ITP.