Recent GWASs have shown that GALNT12 is negatively associated with serum galactose-deficient IgA1 levels resulting in IgA nephropathy [114], and a single nucleotide polymorphism (SNP)—rs2295926, belonging to GALNT12—is strongly associated with rapid radiographic joint destruction in patients with rheumatoid arthritis [115], but the underlying molecular mechanisms are unclear. The gene discussed is GALNT12; the disease is IgA glomerulonephritis.