AKR1D1 and fatty liver disease: When biopsies were categorized on the basis of NAFLD activity score (NAS), reflecting the presence of non-alcoholic steatohepatitis (NASH), as well as on the basis of steatosis percentage, AKR1D1 mRNA levels were lower in those with higher NAS and > 5.5% steatosis (the diagnostic threshold for hepatic steatosis [29,30]) (Fig. 1c–d).