Sweet clues in the urine: novel compound heterozygous SLC5A2 variants causing familial renal glucosuria presenting as recurrent urinary tract infections in an infant

We present a case of a well-thriving infant, who was evaluated for recurrent fever over the past 4 months. History and prior investigations revealed recurrent urinary tract infections (UTIs). A comprehensive workup for recurrent UTIs showed no structural abnormalities of the kidneys or urinary tract. Even after resolved UTIs, the child had persistent glucosuria despite normal blood glucose levels, suggesting a possible tubular disorder. Further evaluation was negative for generalised tubular dysfunction. Whole-exome sequencing (WES) identified novel compound heterozygous variants in the SLC5A2 gene, which encodes the sodium-glucose cotransporter 2, confirming a diagnosis of familial renal glucosuria (FRG). FRG is a rare, benign tubular disorder with no specific treatment; management primarily focuses on preventing and treating associated UTIs. Comprehensive genetic counselling is essential. This case underscores the importance of recognising isolated glucosuria as a potential indicator of an underlying genetic tubular disorder.