Among the 75 patients with infantile intrahepatic cholestasis tested during 2000 -2016, three had ∆<sup>4</sup>-3-oxosteroid 5β-reductase deficiency with AKR1D1 mutations, and three had oxysterol-7α-hydroxylase deficiency with CYP7B1 mutation.
Our aim was to identify mutations in the SRD5B1 gene in patients in whom chenodeoxycholic acid and cholic acid were absent or present at low concentrations in plasma and urine, as these seemed strong candidates for genetic 5beta-reductase deficiency.