Two New Unrelated Cases of Hereditary 1,25-Dihydroxyvitamin D-Resistant Rickets with Alopecia Resulting from the Same Novel Nonsense Mutation in the Vitamin D Receptor Gene
January 2010
in “
Journal of Pediatric Endocrinology and Metabolism
”
TLDR A new gene mutation causes vitamin D resistance and hair loss in two unrelated girls.
The study investigated two unrelated young female patients with hereditary vitamin D resistant rickets (HVDRR) and partial alopecia, both exhibiting severe early onset rickets, hypocalcemia, and hypophosphatemia. Genetic analysis revealed a novel nonsense mutation (R50X) in the vitamin D receptor (VDR) gene, leading to a premature stop codon. This mutation resulted in the absence of VDR protein in skin fibroblasts from one patient, and treatment with 1,25-dihydroxyvitamin D3 failed to induce CYP24A1 gene expression, indicating resistance to 1,25(OH)2D3. The study concluded that this mutation truncates the VDR protein, causing the observed resistance and associated symptoms.