Previous studies found that oestrogen receptor-gene knockout, aromatase knockout, and double oestrogen receptorgene knockout mice displayed elevated triglyceride levels; and mice with congenital oestrogen deficiency developed fatty liver disease.27-30 We believe that women who have fatty liver disease may have an abnormal oestrogen receptor-signalling pathway associated with the regulation of lipid metabolism. This evidence concerns the gene CYP19A1 and fatty liver disease.