Clinical Implication of the C Allele of the ITPKC Gene SNP Rs28493229 in Kawasaki Disease: Association With Disease Susceptibility and BCG Scar Reactivation

Background: a functional single nucleotide polymorphism (SNP) (rs28493229) in the inositol 1,4,5-trisphosphate 3-kinase C (ITPKC) gene has been linked to the susceptibility to Kawasaki disease (KD). The implication remains unclear.

Subjects And Methods: genotyping for the ITPKC polymorphism was conducted on 280 unrelated Taiwanese children with KD and 492 healthy ethnically and gender-matched controls. The clinical manifestations and laboratory data were systemically collected.

Results: the GC and CC genotypes of ITPKC gene SNP rs28493229 were overrepresented in KD patients (GG:GC:CC was 236:43:1, C allele frequency: 8.04%) than those in the controls (GG:GC:CC was 454:37:1, C allele frequency: 3.96%; OR: 2.23, P = 0.001). In KD patients, those with GC or CC genotypes of SNP rs28493229 (19/44) were more likely to have reactivation at the Bacille Calmette-Guérin (BCG) inoculation site than those with GG genotypes (66/236; OR: 1.96, P = 0.044). Such association was particularly strong in patients aged <20 months (OR: 3.26, P = 0.017). The other clinical manifestations were not related to this SNP. There were 160 (57.1%) patients with coronary arterial lesions. The development and the severity of coronary arterial lesion were also not associated with this SNP. Comparison between patients with and without BCG reactivation revealed only one difference: patients with reactivation were younger.

Conclusion: in a cohort from a population with the world's third highest incidence of KD, we demonstrated that the C-allele of ITPKC SNP rs28493229 is associated with KD susceptibility and BCG scar reactivation during the acute phase, although its frequency is lower than that in the Japanese cohort (22.6%), suggesting this SNP contributes to KD susceptibility through induced hyperimmune function reflected in the BCG reactivation.