Vitamin D Dependent Rickets Type IB as a Rare Cause of Rickets, Case Report and Literature Review

Abstract

Aim: The aim of this paper to report one case with vitamin D-dependent rickets, type IB. Methods: Diagnosis has been established based on physical examination, laboratory findings and radiological examination and confirmed by positive gentic mutation. Results: Here we report a 3 year old Saudi female who present with valgus deformity of the feet and delayed motor development with biochemical, radiological evidence of vitamin D disorders. Since vitamin D level was low she was assumed and treated as being due to vitamin D deficiency and treated with cholecalciferol / one alpha for 1 year, but there was no improvement, latter on referred to us where we did gentic study which show a positive gentic mutation at CYP27B1 confirming diagnosis of Vitamin D dependent Rickets 1B, and treatment with Calcitriol then patient show great improvement within 4 weeks, Alkaline phosphatase and PTH both drop to normal levels. Clinical and radiological evidence of the improvement was seen after 3 months of Calcitriol. Conclusions: In this paper, we raise the awareness that Rickets with low vitamin D25 level not always mean deficiency, especially if patient fail to improve with cholecalciferol, and in such case, a rare inherited disorder of Vitamin D activation and action should be looked for, and gentic study is helpful in such cases.