Nephronophthisis complicated with hepatic fibrosis: an autopsy case with rupture of the splenic artery after renal transplantation

Abstract

Nephronophthisis (NPHP) is a disease characterized by a genetic cause of chronic renal failure in children and adolescents, complicated with several extra-renal manifestations such as retinal defect and/or liver fibrosis. Although it is difficult to establish the correct diagnosis, mutations in six genes (NPHP 1-6) have recently been identified. Here we report the case of a 25-year-old male with NPHP with congenital hepatic fibrosis. He showed microscopic hematuria and moderate proteinuria at 20 years. Renal biopsy revealed severe interstitial fibrosis, diffuse tubular atrophy and microcysts at this time with chronic kidney disease stage III (Cr 2.43 mg/dl). C3c was positive in glomeruli in direct immunofluorescent study. Although his mother belongs to a family with polycystic kidney disease, he did not have a novel genetic background of Arg585Cys mutation in exon 8 of the PKD1 gene. Magnetic resonance angiography (MRA) showed typical portal hypertension with spleno-renal shunt caused by biopsy-proven liver fibrosis. Thus, we diagnosed him as having undetermined renal cystic or tubulo-interstitial disease complicated with membranoproliferative glomerulonephritis (MPGN). Renal transplantation was performed in January 2005 after 2 years of dialysis therapy. He was transported to our emergency room because of severe abdominal pain in December 2005. A computed tomographic scan showed massive ascites, which were caused by rupture of the splenic artery. Despite full intensive care including intraluminal coiling of the ruptured aneurysm and extensive blood transfusion, we failed to rescue him on the next day. The autopsy findings revealed severe atrophy of the bilateral kidney with multiple cysts along the cortico-medullary border. Obvious portal hypertension, resulting from congenital hepatic fibrosis, could account for the rupture of the splenic artery with aneurysm formation under pressure/volume overload. This is the first report of a NPHP patient with the complication of hepatic fibrosis emerging from an ADPKD family. As it remains elusive on the phenotype-genotype of the Japanese NPHP population, a registration system of cystic disease of the kidney is required.