Immunodeficiency due to MASP-2 deficiency

MASP2 deficiency, classically defined as MASP2 protein level of less than 100 ng/ml, occurs in about 4% of Caucasians and up to 18% of some African populations. Some MASP2-deficient individuals have increased risk of infection or autoimmune disease, but most are asymptomatic. MASP2 plays a role in activation of the lectin pathway of the complement system; deficiency may thus lead to defects in the complement system (summary by Thiel et al., 2007 and Sokolowska et al., 2015). For a discussion of genetic heterogeneity of lectin complement activation pathway defects, see LCAPD1 (614372). [from OMIM]