Point mutations in the VDR gene are identified in hereditary 1, 25-dihydroxyvitamin D3-resistant rickets, a rare but severe form of rickets.6 VDR gene polymorphism, the milder nucleotide variations that do not cause specific disease, has received attention in relation to the risk of osteoporosis and to bone mineral density since first reported by Morrison et al.7 Given the possible associations between bone metabolism and the VDR polymorphism, rickets may be related to the VDR gene polymorphism. The gene discussed is VDR; the disease is osteoporosis.