Experience of intravenous calcium treatment and long-term responses to treatment in a patient with hereditary vitamin D-resistant rickets resulting from a novel mutation.

Background Vitamin D resistant rickets (HVDRR), is a rare autosomal recessive disorder caused by vitamin D receptor (VDR) gene mutations. There is no standard treatment in HVDRR. Case report The patient was a 3-year-old girl presenting with short stature, genu varum deformity, waddling gait and alopecia. She had hypocalcemia, hypophosphatemia, hyperparathyroidism and normal 1.25-(OH)2D levels. The patient was initially treated with calcitriol and high-dose oral calcium (Ca) for 22 months. The patient was treated with continuous high dose intravenous (i.v.) Ca therapy for 4 months, following initial lack of response to oral Ca and calsitriol. At the end of the 4 months, rickets was dramatically improved and did not recur for 3 years after i.v. Ca therapy. DNA sequence analyses of the VDR gene showed a homozygous novel mutation. Conclusions We identified a novel VDR gene mutation, and we concluded that i.v. Ca therapy from the central catheter is a safe treatment in HVDRR.