ABCB11 and cholestasis: In the liver, the FXR is a BA-sensing receptor involved in the expression of BSEP and is also expressed in the small intestine; the NR1H4 variants cause loss of BSEP expression, leading to the accumulation of toxic bile and hepatocellular damage, with rapidly progressive intralobular cholestasis in the neonatal period [1, 42, 48, 49].