Exostosin-Positive Membranous Nephropathy and Autoimmune Hepatitis: Successful Remission with Immunosuppressive Therapy: A Case Report

Membranous nephropathy (MN) is a common cause of nephrotic syndrome in adults. With the discovery of numerous novel antigens associated with MN, its nomenclature has shifted towards an antigen-based classification. Exostosin-1 (EXT1) and Exostosin-2 (EXT2) are two target antigens associated with autoimmune diseases, especially lupus nephritis. To the best of our knowledge, while MN has been described with autoimmune liver diseases, EXT-positive MN has not been previously described with autoimmune hepatitis (AIH). We report the case of successful remission of EXT-2-positive MN and AIH with steroids, antimetabolite immunosuppressive therapy, and budesonide.