Rickets: not a disease of the past.

Rickets develops when growing bones fail to mineralize. In most cases, the diagnosis is established with a thorough history and physical examination and confirmed by laboratory evaluation. Nutritional rickets can be caused by inadequate intake of nutrients (vitamin D in particular); however, it is not uncommon in dark-skinned children who have limited sun exposure and in infants who are breastfed exclusively. Vitamin D-dependent rickets, type I results from abnormalities in the gene coding for 25(OH)D3-1-alpha-hydroxylase, and type II results from defective vitamin D receptors. The vitamin D-resistant types are familial hypophosphatemic rickets and hereditary hypophosphatemic rickets with hypercalciuria. Other causes of rickets include renal disease, medications, and malabsorption syndromes. Nutritional rickets is treated by replacing the deficient nutrient. Mothers who breastfeed exclusively need to be informed of the recommendation to give their infants vitamin D supplements beginning in the first two months of life to prevent nutritional rickets. Vitamin D-dependent rickets, type I is treated with vitamin D; management of type II is more challenging. Familial hypophosphatemic rickets is treated with phosphorus and vitamin D, whereas hereditary hypophosphatemic rickets with hypercalciuria is treated with phosphorus alone. Families with inherited rickets may seek genetic counseling. The aim of early diagnosis and treatment is to resolve biochemical derangements and prevent complications such as severe deformities that may require surgical intervention.