Association between mannose-binding lectin gene polymorphism and frequent relapses in childhood nephrotic syndrome

Objective: To determine whether mannose-binding lectin(MBL) variant alleles were associated with frequent relapses in childhood nephrotic syndrome(NS). Methods: MBL alleles of codon 54 and promoter region at positions-550 and-221 were genotyped by means of Polymerase Chain Reaction-Restricted Fragment Length Polymorphism(PCR-RFLP)and PCR-Sequence-Specific Primers(PCR-SSP)assay in 32 China Han Nationality children with frequently relapsing NS(FRNS) and 31 with non-frequently relapsing NS(NFRNS),as well as in 32 healthy control subjects. Results: In patients with upper respiratory infections before relapses,the mutant genotype(GGC/GAC and GAC/GAC) frequency of MBL codon 54 was higher in children with FRNS(76.0%) than in children with NFRNS(42.9%).The B allele mutation frequency of MBL codon 54 was higher in children with FRNS than in healthy control subjects(34.4% vs 12.5%,P0.01).It was the same as the frequency of LYB haplotype and the risk of having FRNS given a mutated LYB haplotype assessed by odds ratio(OR)=3.66,95%CI:(1.49-)9.01.However,allele frequencies in promoter region were similar in children with FRNS and healthy control subjects. Conclusion: Our findings suggest that variant MBL genotypes coding for markedly diminished levels of MBL may be one of the genetic factors that determines susceptibility to FRNS and potentially amazing therapy may accrue from future interventions based on these genotypes.