LDLR and metabolic syndrome: However, several studies support that further manipulation in the setting of LDLR knockout can further worsen the dyslipidemia seen in LDLR knockout mice (Coenen et al., 2007; Fuller et al., 2014; Hasty et al., 2001; Ishibashi et al., 1994; Karasawa et al., 2011; Rensing et al., 2014).