Granulomatous nephropathy: have you thought about genetics?

We report here the case of a 16-year-old girl with chronic kidney disease, where biopsy revealed tubulointerstitial nephropathy with granulomas. Initial treatments included immunosuppressive therapy unless genetic testing with exome sequencing identified nephronophthisis due to a homozygous deletion of the NPHP1 gene, marking a unique instance of granulomatous nephropathy related to nephronophthisis. With severe kidney damage, her function has not recovered, necessitating peritoneal dialysis and transplantation. This case highlights the need to consider nephronophthisis in inflammatory interstitial and granulomatous nephropathy, especially when it appears severe and early in life. In addition, it underscores the importance of genetic testing for accurate diagnosis and management in pediatric nephropathies.