Resolution of proximal tubular dysfunction after liver transplantation in ATP8B1 deficiency: A case report

Progressive familial intrahepatic cholestasis type 1 (PFIC1), caused by ATP8B1 deficiency, is a multisystem disorder with extrahepatic manifestations; however, renal involvement has rarely been described. We report a child with genetically confirmed PFIC1 who underwent living donor liver transplantation (LT) for progressive liver disease. Before transplantation, serum creatinine was normal, but a Fanconi‐like proximal tubular dysfunction was characterized by elevated urinary β2‐microglobulin, proteinuria, phosphaturia, hypercalciuria, and metabolic acidosis requiring bicarbonate supplementation. Following transplantation, these abnormalities rapidly resolved, supporting the hypothesis of reversible cholestasis‐associated tubular injury. This case identifies proximal tubular dysfunction as an underrecognized, potentially reversible manifestation of severe, prolonged cholestasis in PFIC1 and supports systematic evaluation of tubular markers before transplantation.