ESPE Abstracts

Background: Vitamin D dependent rickets Type 2A (VDDR2A) is a rare autosomal recessive disorder due to mutation in vitamin D receptor (VDR) leading to hypocalcemia, secondary hyperparathyroidism and signs of rickets. It usually presents with bony deformities along with complete or partial alopecia and is challenging to manage.

Objective: We are reporting case series of two siblings with VDDR2A who were managed in a non-conventional manner (oral calcium and oral vitamin D) in a tertiary care hospital of resource limited country.

Case summary: Two male siblings presented at the age of 11.5 years and 10 years with the concern of short stature and bony deformities since 1 ½ and 4 years of age respectively. They were born to consanguineous parents with a history of two maternal cousins having the same complaints. Examination revealed they both had clinical features of frank rickets with no evidence of alopecia. The investigations showed generalized osteopenia, cupping and frying of epiphysis suggestive of severe rickets on imaging with biochemical evidence of hypocalcemia, hypophosphatemia, raised levels of alkaline phosphatase and raised parathyroid hormone with normal 25-OH Vitamin D levels and raised 1,25(OH)₂D₃ levels, suggesting the diagnosis of calcipenic rickets. Whole exom sequencing of younger sibling confirmed that he was carrying a novel homozygous mutation in VDR, c.1354C@T,p(Arg452Cys), confirming the diagnosis of VDDR2A. They both were started on high oral doses of calcium supplements and calcitriol. They both responded well to the treatment with elder sibling showing complete and younger marked improvement in biochemical and radiological rickets.

Conclusion: VDDR2A is a rare autosomal recession condition which is very challenging to treat and conventionally needs IV calcium to improve rickets. We are reporting 2 siblings with severe rickets and no alopecia carrying a novel mutation in vitamin D receptors and responded well to oral calcium and calcitriol.