In men, increased genetically instrumented transferrin saturation (reported by Allen et al23) was associated with incident haemochromatosis (inverse variance weighted β=0.15, P<0.001), liver disease (β=0.016, P=0.005), liver cancer (β=0.047, P<0.001), osteoarthritis (β=0.012, P=0.005), osteoporosis (β=0.015, P=0.02), but not diabetes (type 1 or 2: β=0.006, P=0.06). The gene discussed is TF; the disease is hereditary hemochromatosis.