Persistent hyperparathyroidism in vitamin D-dependent rickets type 2A does not prevent normalization of hypophosphatemia or healing of the rickets

In a case study of a girl with vitamin D-dependent rickets type 2A (VDDR2A), persistent tertiary hyperparathyroidism did not hinder the healing of rickets or the normalization of hypophosphatemia. Despite elevated parathyroid hormone (PTH) levels, intravenous calcium infusions resolved bone pain and healed rickets within weeks, while phosphate levels normalized. The hyperparathyroidism resolved spontaneously with continued high oral doses of calcium, cholecalciferol, and alfacalcidol, maintaining normocalcemia without additional treatments. The study suggests that intravenous calcium may enhance intestinal phosphorus uptake, aiding in phosphate level normalization even with persistent hyperparathyroidism.