Familial occurrence of autoimmune liver disease with overlapping features of primary biliary cholangitis and autoimmune hepatitis in a mother and her daughter.

We encountered two patients with overlapping features of primary biliary cholangitis and autoimmune hepatitis within the same family. A 68-year-old woman presented at our hospital from a previous medical institution because of the diagnosis of primary biliary cholangitis. Her 49-year-old daughter was admitted with liver dysfunction 4 years later. When compared, these two related patients were found to have overlapping features of primary biliary cholangitis and autoimmune hepatitis. Their human leukocyte antigen haplotype was DRB1*04:05/DRB1*15:02. The clinical and biochemical findings of these two patients immediately improved following treatment with a combination of prednisolone and ursodeoxycholic acid, in accordance with the Japanese guidelines. It is extremely important to identify such pathological conditions as quickly as possible, particularly with the appearance of severe liver dysfunction due to liver cirrhosis, as observed in our case. The Japanese guidelines are considered to be a realistic and useful clinical policy for the swift and efficient treatment of patients with overlapping features of primary biliary cholangitis and autoimmune hepatitis. We suggest that our two patients presented with a genetic predisposition to autoimmune liver disease with overlapping features of primary biliary cholangitis and autoimmune hepatitis within the same family.