ESPE Abstracts

Background: Hereditary Vitamin D-Resistant Rickets (HVDRR) is a rare autosomal recessive disorder caused by mutations in the vitamin D receptor (VDR) resulting in end organ resistant to 1a,25-dihydroxyvitamin D, [1,25(OH)2D]. Majority of HVDRR has Elevated 1, 25(OH)2D which is a hallmark for diagnosis of this disease. High doses of vitamin D, oral calcium and most importantly IV calcium infusion are the mode of therapy in HVDRR.

Aim of study: To evaluate the clinical characteristics, molecular genetics etiology and long term outcome of the largest group of patients with Hereditary Vitamin D-dependent rickets (HVDRR) in Saudi Arabia

Methods: We conducted a retrospective chart review and patient interview to collect the clinical, biochemical and genetic data for all Vitamin D dependent rickets type 2 patients who are currently receiving treatment at King Faisal Specialist Hospital.

Results: We had a total of 42 patients with 57% female and 42 % male, 7 patient treated with high does of oral calcium while 35 of them treated with IV calcium. The median age at presentation is 15.5 months. Alopecia found in 97.61 %, 21.42% presented with bowing legs, 14.28% delayed walking, 9.52% seizure and 2.38% presented with respiratory failure while family history of the disease was positive in 71.42% of total patients. The molecular genetic test for VDR gene showed 4 common mutations (p.Y295* c.885C>A, p.R30* c.88 C>T, p.I268T c.803 T>C, p.V346M c.1036G>A)

Conclusion: We are describing the largest cohort of patients with HVDDR, their clinical biochemical and genetic data. We noticed their good response to IV calcium, also we identified the commonest genetic mutation in our HVDDR patients.