RT-PCR with real-time fluorescence measuring relative FapmRNA abundance between sample groups (13-, 23-, and 33-week-old Apobec1 −/− Ldlr −/− double-knockout mice) showed minimal FapmRNA levels in the proximal aorta in the 13- and 23-week-old mice and high levels of FapmRNA in the 33-week-old mice with advanced atherosclerosis. This evidence concerns the gene LDLR and atherosclerosis.