IGF1 and membranoproliferative glomerulonephritis: Paradoxically, IGF‐1 concentrations were elevated in two of nine adult heterozygous females [Cases 1d, 29.5 nmol/L (RR 11.8‐28.6); and 2a, 32.7 nmol/L (RR 2.7‐28.2)] and were otherwise in the mid‐normal range (mean Z score +0.5 ± 1.5), with the exception of Case 2d who had had renal transplantation following a diagnosis of membranoproliferative glomerulonephritis [IGF‐1, 11.1 nmol/L (RR 8.5‐30.7)].