Inherited IgA glycosylation pattern in IgA nephropathy and HSP nephritis: where do we go next?

New data from Kiryluk et al. show the importance of genetic factors in determining the profile of serum IgA1 O-glycoforms in IgA nephropathy and Henoch–Schönlein purpura nephritis. Elevated serum levels of poorly galactosylated IgA1 O-glycoforms do not, however, appear sufficient in themselves to cause nephritis in these two diseases, and a ‘second hit’ is necessary before changes in IgA1 glycosylation translate into clinical disease. The challenge now is to determine what these genetic factors are.