A novel pathogenic variant of ATP-binding cassette subfamily B member 4 causing gallstones in a young adult.

The low phospholipid-associated cholelithiasis (LPAC) syndrome was reported in European adults with cholelithiasis and a mutation of the ATP-binding cassette subfamily B member 4 (ABCB4). The ABCB4 encodes multidrug resistance 3, which is a phospholipid translocator. Reduced phospholipid transport can lead to the formation of biliary cholesterol stones. Here, we describe a 31-year-old Japanese man diagnosed with recurrent biliary colic. Although he recovered quickly after endoscopic treatment for the most recent presentation, he had a family history of similar problems. His mother had required endoscopic treatment for choledocholithiasis and his maternal aunt had died at age 29 years because of liver failure (etiology unknown). We, therefore, performed genetic analysis, which revealed a heterozygous ABCB4C717S. LPAC syndrome was diagnosed and the patient has received ursodeoxycholic acid for 2 years with no recurrence. The same variant was identified in the patient's mother, who was subsequently found to have a left intrahepatic calculus requiring left-sided lobectomy. She has received ursodeoxycholic acid for 1 year with no recurrence. ABCB4C717S is a novel pathogenic variant, and this is the first patient diagnosed with LPAC syndrome in Japan. We should consider LPAC syndrome in young adults with recurrent cholesterol gallstones to ensure early therapy.