Vitamin D dependent rickets type 2: a case-based review of patient with alopecia and rickets

Abstract

Vitamin D dependent rickets (VDDR) type 2 is a very rare hereditary disease which has an autosomal recessive mode of inheritance. Patients with VDDR type 2 have a mutation in the gene encoding for vitamin D receptor on chromosome 12q12-q14, thus averting normal physiological action of 1,25 vitamin D. It's presents with the developmental delay in motor domain with features of rickets usually in the first year of life. Alopecia totalis has a frequent association with the disease. We are reporting a case of a 5-year-old boy who has a history of difficulty walking since 2 year of life, with a gradually progressive motor weakness course. Patients have a history of alopecia since 2 months of age, which progressed to alopecia totalis. On investigation, serum calcium was 7.2 mg/dl with a very high alkaline phosphate level of 1065 IU/ML with a normal vitamin D level was reported. The initial treatment started with IV calcium followed by 1000mg of oral calcium, along with a high dose of calcitriol. The patient was under periodic follow-up showing improvement in biochemical parameters. We reviewed literature of seven patient out of which 5 patients had alopecia and found 2 patients had enamel hypoplasia and all had features of rickets.