Microsomal triglyceride transfer protein (MTP) as a heterodimer with protein disulfide isomerase (PDI) catalyses lipidation and assembly of apolipoprotein B (ApoB)-containing lipoproteins for secretion by hepatocytes, and MTTP variants have been linked with susceptibility to NAFLD.4 Here, P4HB is linked to metabolic dysfunction-associated steatotic liver disease.