NR1H4 and progressive familial intrahepatic cholestasis: PFIC was previously divided into three types based on the mutated genes of ATP8B1, ABCB11, and ABCB4; however, with the development of diagnostic methods, such as next-generation sequencing and whole-exome sequencing, new mutated genes have been detected in recent years, such as TJP2, NR1H4, and MYO5B, that are responsible for PFIC types IV, V, and VI, respectively [5, 6].