An Unusual Presentation of Vitamin D Dependent Rickets Type 2 with Low 25(OH)D3 Levels and Alopecia: A Case Report of Two Siblings

The document presents a case report of two siblings with Vitamin D-dependent rickets type 2 (VDDR2) and alopecia totalis. VDDR2 is a rare autosomal recessive disorder caused by a mutation in the Vitamin D receptor gene or overexpression of the binding protein, leading to end-organ resistance to 1,25 (OH)2 vitamin D3 or defective hormonal actions. It typically presents with growth retardation in the first year of life and is often associated with alopecia totalis and elevated levels of 1, 25(OH)2 D. The siblings in this report showed clinical and radiological features of rickets and alopecia totalis. The case is unusual as it features low 25(OH)D3 levels, a characteristic not commonly seen in VDDR2.