Idiopathic membranous nephropathy is associated with autoantibodies against the phospholipase A2 receptor (PLA2R1) in about 70% of patients. This study identifies another antigen, thrombospondin type-1 domain-containing 7A (THSD7A), which accounts for about 10% of cases. Idiopathic membranous nephropathy is an autoimmune disease and a common cause of the nephrotic syndrome in adults. 1 In 2009, the phospholipase A2 receptor 1 (PLA2R1), a protein that is expressed in glomerular podocytes, was discovered as the major antigen involved in the pathogenesis of adult idiopathic membranous nephropathy. 2 As confirmed by a number of subsequent studies, about 70% of patients with idiopathic membranous nephropathy have circulating autoantibodies against PLA2R1. 2 – 6 The remaining patients, approximately 30% of those with idiopathic membranous nephropathy, have no obvious secondary cause of the disease, and it is thought that other endogenous glomerular antigens may be . . .