A Rare Case of Hereditary 1,25-Dihydroxyvitamin D Resistant Rickets

The document discusses a rare case of hereditary 1,25 (OH)2D resistant rickets, also known as vitamin D-dependent rickets type 2A (VDDR2A), which is caused by mutations in the vitamin D receptor gene. The case involves a 37-year-old male with a history of bone nonunion, multiple childhood fractures, and some hair loss since age 30. Laboratory tests revealed normal renal and thyroid function, but low calcium and phosphorus levels, and elevated 1,25 (OH)2D levels. Genetic testing confirmed a heterozygous mutation in the VDR gene. This condition, characterized by severe rickets, bone pain, dental issues, and alopecia, requires management with high doses of calcium and vitamin D. The case underscores the importance of thorough evaluation and understanding of metabolic bone diseases.