分子与遗传医学

Incidental Finding of Renal Impairment Leading to a Diagnosis of Nephronophthisis

Abstract

Pinzon MB, Chau K and Tarafdar S

This case report describes the diagnosis of a familial juvenile nephronophthisis in a 17-year-old boy and emphasises on the increasing importance of genetic testing in patients with chronic kidney disease. A 17-yearold Iraqi refugee presented with abdominal pain and was incidentally found to have renal impairment (creatinine 279 μmol/L, urea 12.6 mmol/L, calculated eGFR for age 28 ml/min/1.73 m²). Urinalysis showed no proteinuria nor haematuria and renal ultrasound and computed tomography revealed small kidneys (left=8.4 cm and right=7.9 cm). The patient's brother had end-stage renal disease and commenced on peritoneal dialysis at the age of 19 with a presumed diagnosis of cystic renal hypodysplasia. Genetic testing revealed homozygous deletion of 2q13 that encompasses NPHP1 giving a diagnosis of juvenile nephronophthisis. Nephronophthisis is an autosomal recessive disorder characterised by normal to small cystic kidneys and an insidious onset of end-stage renal disease. It is the most common genetic renal disease in the first two decades of life and mortality is related to the complications of renal failure. It is caused by mutations in the NPHP genes, which encode proteins involved in the function of primary cilia, centrosomes and basal bodies. Nephronophthisis may be isolated or part of a syndrome and diagnosis is established by genetic testing.