A 12-year-old girl from Ukraine was hospitalized for evaluation of a history of long-bone fractures and failure to thrive. On initial presentation, she had hypocalcemia (calcium level, 6.7 mg per deciliter [1.7 mmol per liter]), a low 25-hydroxyvitamin D level (5 ng per milliliter [12 nmol per liter]), an elevated parathyroid hormone level (435 pg per milliliter), an elevated alkaline phosphatase level (546 U per liter), and a normal phosphorus level (4.1 mg per deciliter [1.3 mmol per liter]). These findings were consistent with vitamin D-deficient rickets. She also showed multiple sequelae of long-standing rickets, including costochondral swelling (rachitic rosary), ...