Remission of Nephrotic Proteinuria after Liver Transplantation in a Case of Abernethy Malformation Type Ib and Membranoproliferative Glomerulonephritis

Abernethy malformation is a rare congenital vascular anomaly defined by the absence or severe hypoplasia of the portal vein, resulting in portosystemic shunting. The metabolic and immunologic consequences such as hepatic encephalopathy and pulmonary complications are well recognized. However, renal involvement of Abernethy malformation has been reported rarely . We report a 13-year-old boy who presented with severe anemia, pneumonia and nephrotic-range proteinuria (14.18 g/24 h). Imaging demonstrated type Ib Abernethy malformation, with complete agenesis of the portal vein and direct drainage into the inferior vena cava. Kidney biopsy showed immune complex–mediated membranoproliferative glomerulonephritis (IC-MPGN) with a”full house” immunofluorescence pattern and hypocomplementemia. Biomarkers for autoimmune disease, infection and monoclonal gammopathy were negative. The patient showed a limited response to methylprednisolone, cyclophosphamide and intravenous immunoglobulin. However, proteinuria declined to 1.2 g/24 h four weeks after liver transplantation,. The complement and hemoglobin levels also normalized. The patient currently has negative proteinuria on tacrolimus monotherapy. This case illustrates a potential association between Abernethy malformation and membranoproliferative glomerulonephritis (MPGN). It also highlights the importance of vascular imaging in patients with unexplained glomerulonephritis and hypocomplementemia accompanied by hepatic anomalies.