Expanding Phenotype of Nephronophthisis-Related Ciliopathy: an Elderly Patient with Homozygous RPGRIP1L Mutation

Nephronophthisis-related ciliopathies (NPHP-RC) are autosomal recessive disorders characterized by renal corticomedullary cysts with the extrarenal symptoms. Typically, patients with NPHP-RC reach end-stage kidney disease (ESKD) before the age of 30 years. We herein report a Japanese woman with NPHP-RC who had unusually delayed progression to ESKD after 6 decades. She exhibited liver dysfunction at the age of 23 years. She also showed mild renal dysfunction at the age of 43 years. Ultrasonography revealed bilateral multiple renal cysts with loss of corticomedullary differentiation. Her liver and renal functions gradually deteriorated. She was diagnosed with liver fibrosis as a result of biopsy, and initiated the maintenance hemodiafiltration therapy for ESKD at the age of 61 years. Because of a unique combination of multiple renal cysts and liver fibrosis, ciliopathy was suspected and medical exome analysis was performed. A novel homozygous missense mutation was identified in RPGRIP1L (c.1810G>A p.Glu604Lys), a causative gene for NPHP-RC. To the best of our knowledge, this patient is the oldest one who progressed to ESKD in NPHP-RC. Our case illustrates that NPHP-RC should be included in the differential diagnosis of the patient with corticomedullary polycystic kidneys accompanied by the extrarenal organ involvements, even if the patient is elderly.