Bones, Stones, and Hematuria - Connecting the Dots.

We report a 12 yr old boy who presented with recurrent gross hematuria, polyuria and rickets with growth failure. Investigations showed bilateral renal calculi with small kidneys on ultrasonography along with hypercalciuria; hypomagnesemia and reduced kidney function. His younger sibling also had nephrocalcinosis hypomagnesemia. The genetic analysis done in view of recurrent renal calculi with chronic kidney disease showed a homozygous missense variant (c.392G>A) at exon 4 of CLDN 16 gene suggestive of Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC). The younger sibling had a similar homozygous mutation and the parents were heterozygous carriers.