Extremes of L-ficolin concentration in children with recurrent infections are associated with single nucleotide polymorphisms in the FCN2 gene

L- ficolin ( also called ficolin- 2, P35 or hucolin) is a soluble pattern recognition molecule of suspected importance in anti- microbial immunity. It activates the lectin pathway of complement and acts as an opsonin. L- ficolin, encoded by the FCN2 gene, recognizes microbial polysaccharides and glycoconjugates rich in GlcNAc or GalNAc. We report here data concerning four single nucleotide polymorphisms ( SNPs) of the FCN2 gene and their relationship to L- ficolin serum concentrations. There are two pairs of SNPs in linkage disequilibrium:ss32469536 ( located in promoter) with rs7851696 ( in exon 8) and ss32469537 ( promoter) with ss32469544 ( exon 8). We selected groups possessing low or high serum L- ficolin concentrations ( <= 2 mu 8 mg/ ml or > 4.5 mu g/ ml, respectively) from Polish children suffering from recurrent respiratory infections ( n = 146). Low L- ficolin levels were associated with variant alleles for ss32469536 and rs7851696 and normal alleles for ss32469537 and ss32469544. Conversely, high L- ficolin levels were associated with variant alleles of ss32469537 and ss32469544. FCN2 genotyping should be a valuable additional tool for disease association studies.