AKR1D1 and Cholestatic liver disease: Elevated 3-oxo-Δ4 bile acids in neonates and children with severe cholestatic liver disease was at first interpreted as being due to an autosomal recessive inborn error of metabolism that affected Δ4-3-oxo-steroid 5β-reductase10, 11 (now known as AKR1D1).