Nephronophthisis: clinical features and approach to the diagnosis

Abstract

Nephronophthisis (NPH) belongs to cystic renal diseases with the cystic formation in corticomedullary border of the kidney. NPH accounts for approximately 5% of end-stage renal disease occurring in childhood, is characterized by renal medullary cyst formation, tubulointerstitial nephritis accompanied by progressive glomerular sclerosis and hyalinization of glomeruli. NPH shows mainly autosomal recessive inheritance. Polyuria and polydipsia, and urinary concentration defect are demonstrated in early childhood (4–6 years of age). The urine often shows low specific gravity specific density and low-molecular-weight protein. Typical extrarenal manifestations are helpful for the diagnosis. NPHP1, the gene most often responsible for juvenile nephronophthisis, encodes the nephrocystin-1 molecule. However, NPHP gene mutation was found in about 30%. Recently, whole exome sequencing allows increased detection of mutation caused by NPH. Diagnostic criteria for NPH was provided in Japan, helping for the diagnosis for cases without definitive diagnosis in the future.