Effect of Calcium Supplementation on Bone Deformity and Histopathological Findings of Skin Papules in a Pediatric Patient with Vitamin D-Dependent Rickets Type 2A: A Case Report

This case report discusses a pediatric patient with vitamin D–dependent rickets type 2A (VDDR2A), an autosomal recessive disease caused by pathogenic variants of the vitamin D receptor (VDR) gene. The patient exhibited resistance to active vitamin D treatment, which did not improve bone deformities or laboratory findings. However, oral calcium lactate supplementation significantly improved these conditions. The patient also experienced alopecia and skin papules, which are associated with VDR variants affecting the dimerization with the retinoic X receptor. Despite treatment, the skin papules and hair loss did not improve, and the report includes histopathological findings of the skin papules.