ABCB4 and cirrhosis of liver: Notably, variants in ABCB4 can result in a complete loss of protein expression or can be minor, leading to a broad clinical spectrum of ABCB4-associated diseases - from severe progressive familial intrahepatic cholestasis type 3 with early development of liver cirrhosis and the need for liver transplantation, to less severe diseases such as low phospholipid-associated cholelithiasis, intrahepatic cholestasis of pregnancy, or DILI.