There are also genetic factors linking cholesterol metabolism and AD, though ApoE is the only gene with replicable evidence, several candidate genes involved in lipid metabolism like A2M (alpha-2-Macroglobulin), LRP (lipoprotein receptor related protein), IDE (insulin degrading enzyme), ABCA1 (ATP-binding cassette transporter), ACAT (Acyl-CoA cholesteryl acyl transferase), CYP 46 (Cytochrome P450, family 46, convertscholesterol to 24S-hydroxycholesterol) are being investigated for putative roles with mixed results.[17]. The gene discussed is APOE; the disease is Alzheimer disease.