PNPLA3 and metabolic dysfunction-associated steatotic liver disease: The HepG2 cell line, which is widely used to study liver diseases, was found to carry homozygous PNPLA3 M148M genotype.17 This characteristic makes HepG2 cells a natural mutation model in which to study the function of human PNPLA3 I148M and its role in NAFLD.