ABCB4 and progressive familial intrahepatic cholestasis type 3: In one case, an mRNA‐loaded LNP formulation was developed for the treatment of progressive familial intrahepatic cholestasis type 3 (PFIC3), which occurs due to a defective ABCB4 gene that normally encodes for a phosphatidylcholine (PC) transporter necessary for biliary micelle formation (Figure 7).[183] After multiple injections of the nanoparticles formulated with codon‐optimized, nucleoside‐modified human ABCB4 mRNA, significant improvements in body and liver weight, biliary PC concentrations, and other serum biomarkers were observed in BALB/c.Abcb4–/– mice.