Alzheimer’s disease has also shown to be inherited through a more complex pattern rather than a single gene mutation. For example, the gene ‘apolipoprotein E’ (which is found in chromosome 19) transports lipoproteins, vitamins and cholesterol into the lymph system and consequently into the blood.
This gene has three alleles (APOE e2, APOE e3 and APOE e4), and we each have two copies of the gene (one from each parent due to the fusion of the sperm and egg which each contain one of each chromosome due to meiosis). Alleles are different versions