Abstract

Hereditaryhypophosphatemic rickets with hypercalciuria ( HHRH) is a rare genetic condition with Autosomal recessive inheritance with a  prevalence of 1 in 250000. It is due to mutation in SLC4A3 gene. Correct diagnosis of this condition is  important as treatment with active vitamin D metabolites are contraindicated. Evolution of the disease despite initial completely normal bio chemistry has ben observed causing  diagnostic confusion. First child presented  at the age of 5.5 year with features of rickets. He had abnormal bone profile with normal vitamin D levels. urinary phosphate studies were compatible with HHRH. He was treated with phosphate supplementation and  Potassium citrate. He has well responded to the treatment. Second child initially presented at 1.5 years of age with bowing and family history of hypercalciuria. All investigation findings including urinary phosphate studies were within normal limits.  At the age of 2.5 year, he again presented with worsening of bowing. Bio chemical and urinary investigations were repeated. Laboratory findings were  compatible with HHRH. It  highlights the importance of repeated investigations despite initial normal parameters if the initial clinical suspicion is strong and clinical and investigation based diagnosis of this rare genetic disease in resource limited setting.