Osteolytic and bone demineralisation processes that take place during ageing may explain the negative correlation of plasma OMD levels with vitamin D.42In addition, the positive correlation of circulating OMD levels with klotho44 and sclerostin,23 both strong inhibitors of calcification,45, 46 implied a possible protective function of OMD in the mineralisation process. The gene discussed is SOST; the disease is occult macular dystrophy.