Treatment of Rickets in Vitamin D-Dependent Rickets Type 2B (HNRNPC Mutation)

Vitamin D-dependent rickets type 2B (VDDR2B) results from mutations in the HNRNPC gene that impair vitamin D receptor signaling. The clinical consequences closely parallel those of VDDR2A, and management is structured accordingly.

This protocol addresses patients with VDDR2B in whom an HNRNPC mutation underlies defective vitamin D receptor signaling, disrupting calcium homeostasis and driving the rickets phenotype.

Because the receptor-signaling defect mirrors VDDR2A, treatment centres on high-dose oral calcium supplementation — with intravenous calcium available when oral intake is insufficient — alongside active vitamin D metabolites or specific vitamin D preparations. The full selection criteria, sequencing, and monitoring parameters are in the complete protocol.

• Normocalcemia
• Normalization of PTH levels