While impaired Ldlr function in humans leads to elevated plasma cholesterol and premature cardiovascular disease due to reduced uptake of cholesterol-rich LDLs (Hobbs et al., 1990; Fass et al., 1997), the effect in mice is similar yet less severe (Ishibashi et al., 1993; Osono et al., 1995). The gene discussed is LDLR; the disease is cardiovascular disorder.