inositol-1-4-5-trisphosphate and Mucocutaneous-Lymph-Node-Syndrome

Single-nucleotide polymorphisms (SNPs) of several genes are linked to the etiopathogenesis of Kawasaki disease (KD). Association of SNPs of inositol 1,4,5-triphosphate-3-kinase C (ITPKC) gene with susceptibility to KD and coronary artery lesions (CALs) has been observed in children of certain ethnicities, but not from others. The present study was planned to explore this genetic association in the North Indian cohort.. Fifty children with KD and 50 age- and sex-matched controls were studied for two SNPs (rs28493229 and rs2290692) of the ITPKC gene using polymerase chain reaction and restriction fragment length polymorphism. Findings were confirmed by Sanger sequencing. A meta-analysis was also carried out for GG and CC genotypes of the SNPs.. There was significant association between KD susceptibility and CG + GG genotype of rs2290692 (p = 0.015, odds ratio = 4.1, 95% confidence interval = 1.38-13.83). None of the single alleles or genotypes of the SNPs of ITPKC were, however, significantly associated with KD susceptibility. A meta-analysis also did not show any significant association of these SNPs to KD susceptibility.. Our findings suggest that ITPKC gene SNPs (rs28493229 and rs2290692) did not have a significant association with susceptibility to KD in children from North India. Larger multicentric studies incorporating different ethnicities are required to understand the genetic basis of KD.. While SNP rs28493229 of the ITPKC gene is not found to be associated with susceptibility to KD, the combined genotype of SNP rs2290692 is shown to be associated. Impact of ITPKC gene SNP on KD is different across different races and ethnicities. We could find an association of the combined genotype of rs2290692 with it in the Indian population. This study highlights that phenotype and genotypic association of KD varies with ethnicities. Larger multicentric studies are required to reach a conclusion regarding the genetic association of KD.

Topics: Case-Control Studies; Child; Genetic Predisposition to Disease; Genotype; Humans; India; Inositol 1,4,5-Trisphosphate; Mucocutaneous Lymph Node Syndrome; Phosphotransferases (Alcohol Group Acceptor); Polymorphism, Single Nucleotide

Recently, a single nucleotide polymorphism (SNP) of the inositol 1,4,5-triphosphate kinase C (ITPKC), rs28493229, was found to passively confer susceptibility for Kawasaki syndrome (KS) and subsequent coronary arterial lesions. This association is believed to be the result of defective phosphorylation of inositol 1,4,5-triphosphate (IP3), which releases calcium from intracellular stores, resulting from reduced genetic expression of ITPKC in carriers of the SNP. Reduced ITPKC activity would increase IP3 levels, and thus, increase calcium release. We hypothesized that an environmental agent which influences IP3-mediated calcium release is potentiated by the ITPKC SNP. This led us to an attractive candidate, thimerosal, an organomercurial medical preservative still used in several pediatric vaccines. Thimerosal is well-known to sensitize IP3 receptors via its induction of oxidative stress, resulting in enhanced release of intracellular calcium with distinctive consequences for various cell types. Dysregulated calcium signaling in T cells and other immune cells can result in autoimmunity, while hyperpolarization of vascular smooth muscle cells secondary to the stimulation of calcium-activated potassium channels can result in increased vascular permeability and arterial relaxation. We propose that ITPKC susceptibility in KS is related to its synergy with environmental triggers, such as thimerosal, which alter calcium homeostasis and promote oxidative stress. Therefore, carriers of the ITPKC SNP are more susceptible to thimerosal-induced autoimmunity and coronary arterial lesions observed in KS. This would explain why only a susceptible subset of children develops KS although pediatric thimerosal exposure is nearly universal due to vaccination. As was experienced with the infantile acrodynia epidemic, only 1 in 500 children developed the disease although pediatric mercury exposure was nearly ubiquitous due to the use calomel teething powders. This hypothesis also mirrors the current leading theory for KS in which a widespread infection only induces the disease in susceptible children. We conclude that KS may be the acute febrile form of acrodynia.

Topics: Acrodynia; Autoimmunity; Calcium Signaling; Capillary Permeability; Child; Coronary Vessels; Gene-Environment Interaction; Genetic Predisposition to Disease; Humans; Inositol 1,4,5-Trisphosphate; Mucocutaneous Lymph Node Syndrome; Oxidative Stress; Phosphotransferases (Alcohol Group Acceptor); Polymorphism, Single Nucleotide; Thimerosal