To investigate the possible association between polymorphisms of the mannose-binding lectin gene (MBL2) and susceptibility to juvenile idiopathic arthritis (JIA).
We performed a case-control association study including 118 Hungarian patients with JIA and 118 sex-matched healthy controls. MBL genotyping for the 3 mutant structural alleles at codons 54 (B), 57 (C), and 52 (D) in exon 1 and the promoter polymorphisms at position -550 (HL) and -221 (YX) were carried out by real-time PCR allelic discrimination. Serum level of MBL was determined by ELISA.
Variant allele frequencies of both codon 52 and 57 polymorphisms in the MBL2 gene were significantly overrepresented in JIA (p=0.001 and p=0.004, respectively). The frequency of low MBL genotypes (XA/XA, YA/YO, XA/YO, and YO/YO) in JIA was higher than that in healthy controls (p=0.001). Serum MBL concentrations were found to be significantly lower in JIA patients versus control subjects (p=0.001). The 2 promoter polymorphisms and codon 54 SNP of the MBL2 gene were not associated with JIA.
Our findings suggest that genetically determined low MBL levels may predispose children to JIA in a Hungarian population. These data warrant further research to investigate the role of the lectin-dependent complement system in the pathogenesis of JIA.