Mice heterozygous for the ENU-induced Tmed299J/+ allele had decreased levels of TMED2 and TMED10, dilated endoplasmic reticulum membrane and increased phosphorylation of eIF2α (indicating ER-stress and activation of the UPR), increased expression of Srebp1a and 2 at the newborn stage, and an increased incidence of non-alcoholic fatty liver disease (NAFLD). This evidence concerns the gene SREBF1 and metabolic dysfunction-associated steatotic liver disease.