This assumption was supported by the negative correlation between circulating cholesterol and the expression level of hepatic cyp7a1, as cyp7a1 deficiency has been reported to lead to hypercholesterolemia (Pullinger et al., 2002; Erickson et al., 2003; Qayyum et al., 2018). Here, CYP7A1 is linked to familial hypercholesterolemia.