ATP8B1 and progressive familial intrahepatic cholestasis: Several cholestatic disorders have been characterized as mutations in genes involved in bile formation, including ATP8B1 (a phospholipid flippase), BSEP, multidrug resistance protein 3 (MDR3/ABCB4), tight junction protein‐2 (TJP2), farnesoid X receptor (FXR/NR1H4), and myosin VB (MYO5B), leading to progressive familial intrahepatic cholestasis (PFIC) 1–6, respectively (Amirneni et al, 2020).