Vitamin D Insufficiency is Not Associated With Pediatric and Adolescent Immune Thrombocytopenia: A Study in Conjunction With its Receptor Genetic Polymorphisms

Idiopathic thrombocytopenic purpura (ITP) is a heterogeneous immunologic disorder. Vitamin D has immune-modulatory effects. The pleiotropic effects of vitamin D are exerted via vitamin D receptor (VDR) and its genetic alterations could influence its functions. In our study, we measured the serum 25-hydroxyvitamin D levels in 98 Pediatric and Adolescent ITP patients, in addition to 100 apparently healthy controls. Genetic polymorphisms of the VDR gene FokI , BsmI , ApaI , and TaqI were tested using specific restriction enzymes for each polymorphism. Vitamin D deficiency in the studied Pediatric age was a dominant factor, but it was found not to be associated with Pediatric ITP. However, patients carrying the FokI CC genotype had statistically higher vitamin D levels compared with those carrying other genotypes ( P =0.036). Patients who were carriers of the BsmI G allele had a nearly 2-fold higher risk of ITP (odds ratio: 2.203; 95% confidence interval: 1.467-3.309). Therefore, the BsmI polymorphism of VDR could be considered a molecular risk factor for ITP.