PNPLA3 and alcoholic fatty liver disease: The identification of the PNPLA3 variant rs738409, which encodes for an amino acid substitution of isoleucine to methionine at position 148 (p.Iso148Met) of the protein in patients with alcoholic or non-alcoholic fatty liver disease, shed important light on the enigmatic role of PNPLA3 in hepatic lipid and energy metabolism [174,175,176,177].