# Granulomatous nephropathy: have you thought about genetics?

## TL;DR

A teenage girl with kidney disease had her condition linked to a genetic cause, highlighting the importance of genetic testing in diagnosing rare kidney disorders.

## Contribution

This case uniquely connects granulomatous nephropathy with nephronophthisis caused by a specific genetic mutation in NPHP1.

## Key findings

- A homozygous deletion in the NPHP1 gene was identified as the cause of nephronophthisis in a patient with granulomatous nephropathy.
- The case emphasizes the importance of genetic testing in diagnosing severe and early-onset pediatric nephropathies.
- The patient's kidney function did not recover, requiring dialysis and transplantation.

## Abstract

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.