A genetic predisposition to autoimmune liver disease can cause overlapping cases of autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) within the same family, according to a case report from Japanese researchers.

A 68-year-old woman and her 49-year-old daughter were admitted to the hospital for liver dysfunction, 4 years apart. The mother had been diagnosed with PBC at a previous hospital, but was moved after treatment with 600 mg ursodeoxycholic acid (UDCA) was ineffective. The daughter had no previous diagnosis and had a variety of symptoms at admission, including jaundice, general fatigue, and darkness of the urine.

Both the mother and the daughter were negative for hepatitis A, B, and C. A simplified International Autoimmune Hepatitis Group score revealed probable AIH for both patients, and both patients were diagnosed with autoimmune liver disease with overlapping features of PBC and AIH. Treatment with UDCA and prednisolone was effective for both patients.

In a familial study, the mother and her two daughters were tested for liver function, autoantibodies, and human leukocyte antigen (HLA) haplotype. The second daughter, who was healthy with no history of liver dysfunction, had normal liver function, negative ANA, and positive AMA-M2 antibody, but had an HLA haplotype different from that of the mother and the first daughter. No difference in medication use, smoking status, alcohol consumption, or obstetric history was seen.

“The exact mechanism underlying the onset of PBC and AIH overlap within the same family remains unclear. Therefore, it is very important to monitor the healthy second daughter closely as she was positive for the AMA-M2 antibody, as this might yield further knowledge with regard to what factors influence the onset of PBC and AIH overlap within the same family,” the investigators noted.

Find the full study in the Journal of Clinical Gastroenterology ( doi: 10.1007/s12328-016-0676-1 )