SUN-332: A Rare Case of Hereditary 1,25 (OH)2D Resistant Rickets

This 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 fractures, and some hair loss. Laboratory tests revealed normal vitamin D levels but elevated 1,25 (OH)2D, indicating tissue resistance to vitamin D. Genetic testing confirmed a mutation associated with VDDR2A. This condition, characterized by symptoms such as severe rickets, bone pain, and alopecia, requires management with high doses of calcium and vitamin D. The case underscores the importance of understanding metabolic bone diseases and vitamin D metabolism.