For example, in addition to the high frequency CFTR, HFE and SERPINA1 pathogenic variants, two patients with progressive familial intrahepatic cholestasis type 3 carried an ABCB4 Ala934Thr missense variant which has a MAF of 1.2% in African-American populations, and should be interpreted as a pathogenic variant (Supplementary Information 2). This evidence concerns the gene SERPINA1 and progressive familial intrahepatic cholestasis type 3.