Tumor necrosis factor induced protein 3 gene polymorphism and the susceptibility to chronic primary immune thrombocytopenia in Egyptian children: a case-control study

Primary immune thrombocytopenia (PIT) is an acquired auto-immune disease characterized by decreased platelet count with increased bleeding tendency. The tumor necrosis factor associated induced protein-3 (TNFAIP3) codes for the ubiquitin-modifying enzyme that is indispensable for limiting inflammation. TNFAIP3 single-nucleotide polymorphisms (SNP) has been implicated in the susceptibility to multiple auto-immune diseases. We aimed to study the distribution of TNFAIP3 (rs5029939 C>G) SNP and the possible association of the studied polymorphism with the susceptibility to chronic PIT and the response to treatment in a sample of the Egyptian pediatric chronic PIT patients. This is a case-control study performed on 40 chronic PIT patients and 50 age- and gender-matched healthy controls. DNA samples from both groups were tested for TNFAIP3 (rs5029939 C>G) SNP using polymerase chain reaction-restriction fragment length polymorphism assay. TNFAIP3 (rs5029939 C>G) genotype distribution showed no statistically significant difference between PIT cases and controls [CC 77.5% vs. 82.5%, and CG 22% vs. 18%, respectively; OR (95% CI), 1.323 (0.470–0.723); p, 0.596]. The minor allele frequency (MAF) of rs5029939-G was comparable between the 2 groups (0.11 vs. 0.09) [OR (95% CI), 1.282 (0.484–3.397); p, 0.617]. No statistically significant difference was observed between chronic PIT patients carrying the mutant heterozygous genotype (CG) achieving complete response and those with no response [OR (95% CI), 1.667 (0.165-16.810); p > 0.05]. The MAF of rs5029939-G was comparable between both groups [OR (95% CI), 1.571 (0.175–14.111); p > 0.05]. This study showed no liability of patients carrying TNFAIP3 (rs5029939 C>G) polymorphism to develop chronic course of the disease or to achieve complete response to treatment. TNFAIP3 (rs5029939 C < G) SNP plays no role in either susceptibility to chronic PIT in the studied sample of Egyptian pediatric population or their response to treatment.