Functional MASP2 single nucleotide polymorphism plays no role in psoriasis

Background Psoriasis is a heritable disease and genome-wide scans have implicated several loci of susceptibility. The gene for MASP-2, a protease involved in complement activation, is located within one of these loci on chromosome 1p. Objectives To assess whether partial or total MASP-2 deficiency is a risk factor for developing psoriasis. Methods We screened a cohort of patients affected by plaque psoriasis and their parents by restriction fragment length polymorphism analyses. Results We detected a single nucleotide polymorphism that leads to an amino acid exchange, which results in dissociation of MASP-2 from a carbohydrate recognition complex. Conclusions We show that this mutant allele is not associated with psoriasis. There was no favoured transmission from parents to affected offspring. The calculated allele frequency in this psoriasis group (Scottish and English) was 0.0326, and in the unaffected group 0.0379.