Encode HNF-1α which activates the transcription of apoM, a major component of HDL particles (Richter et al., 2003), and it can affect plasma levels of HDL, reverse cholesterol transport and cholesterol metabolism (Babaya et al., 2003). Hnf1a–/– mice had abnormal HDL particles and suffered from hypercholesterolemia (Shih et al., 2001). Besides, HNF-1α can transactivate insulin I gene (Emens et al., 1992) and it had been reported that Hnf1a knockout mice developed non-insulin-dependent diabetes mellitus (Lee et al., 1998). Here, APOM is linked to Hypercholesterolemia.