TNFRSF11A and focal segmental glomerulosclerosis: We analyzed mRNA expression of RANK and RANKL in normal kidney tissues (n = 3), focal segmental glomerulosclerosis (FSGS, n = 12), IgA nephropathy (n = 14), and membranous nephropathy (MN, n = 16), and the latter three groups are with proteinuria.