GPT and fatty liver disease: Measurement of MAFLD phenotypes in previous genome-wide association study (GWAS) ranged from histology (past main reference standard), with a risk of sampling bias and possible underestimation of disease severity [3,4]; imaging, including the new gold standard for quantification of hepatic steatosis by magnetic resonance imaging proton density fat fraction (MRI-PDFF) [5] and estimating MRI-PDFF by deep learning or mathematical models [6–8]; clinical diagnosis based on diagnostic codes and electronic health records [9,10]; to liver blood tests such as alanine aminotransferase (ALT) [11,12].