Nephrotoxic effect of vitamin D therapy in vitamin D refractory rickets.

vitamin D refractory rickets isararedisease whichmaybeinherited asasexlinked dominant (Winters etal.,1958), andis characterized bythedevelopment ofthestigmata ofrickets inthefirst yearoflife.Thereisoften considerable delaybefore thecorrect diagnosis is made,andbythenthere maybesomeretardation ofgrowth(Fraser andSalter, 1958).Therickets canbehealedbyverylarge dosesofvitamin D (Albright, Butler, andBloomberg, 1937), butthe margin between thetherapeutic doseandthetoxic doseofvitamin D issmall(Fraser andSalter, 1958).Vitamin D intoxicdosescauseshypercalcaemia leading to nephrocalcinosis (Parfitt, 1964;David, Verner, andEngel, 1962). We haverecently studied 4children withvitamin D refractory rickets toassess thelikelihood of development oftoxic effects fromcarefully monitored long-term treatment withvitamin D. Material andMethods