No evidence for a role of cosmc-chaperone mutations in European IgA nephropathy patients

Altered IgA1 galactosylation is involved in the pathogenesis of IgA nephropathy (IgAN). The galactosyltransferase core-1 beta3-galactosyltransferase-1 (C1GALT1) and its chaperone cosmc are specifically required for O-galactosylation of the IgA1 hinge region. Mutations in the cosmc gene result in a secondary loss of function of C1GALT1 with subsequent undergalactosylation of glycoproteins. Mosaic mutations of cosmc have been shown to result in autoimmune disease. We hypothesized that cosmc mutations might contribute to the altered IgA1 galactosylation in IgAN patients.