Genetics play a key role in Alzheimer’s disease, but it’s not as simple as you might think. The genetic influence on Alzheimer’s disease is complex and multidimensional, involving both rare deterministic genes and frequent disease risk genes.
The role of aging
Rare deterministic genes are those that directly cause a disease, guaranteeing that anyone who inherits them will develop the disorder. In the case of Alzheimer’s disease, such genes are found in less than 1% of cases and are usually associated with early-onset Alzheimer’s disease. These include mutations in the APP, PSEN1 or PSEN2 genes. In contrast, most cases of Alzheimer’s disease are linked to risk genes. These genes make an individual more susceptible to the disease, but do not guarantee that it will occur. For example, the APOE ε4 gene variant is the most significant genetic risk factor for late-onset Alzheimer’s disease, increasing the risk and lowering the age of onset of the disease.
The role of aging
In addition, people with Down syndrome carry a third copy of chromosome 21, which increases the production of amyloid precursors and thus the risk of early-onset Alzheimer’s disease. Understanding these genetic factors has been possible thanks to advances in genetic research, with the use of genome-wide association studies (GNJAS) helping to identify numerous genes associated with an increased risk of Alzheimer’s disease.
Rare deterministic genes are those that directly cause a disease, guaranteeing that anyone who inherits them will develop the disorder. In the case of Alzheimer’s disease, such genes are found in less than 1% of cases and are usually associated with early-onset Alzheimer’s disease. These include mutations in the APP, PSEN1 or PSEN2 genes. In contrast, most cases of Alzheimer’s disease are linked to risk genes. These genes make an individual more susceptible to the disease, but do not guarantee that it will occur. For example, the APOE ε4 gene variant is the most significant genetic risk factor for late-onset Alzheimer’s disease, increasing the risk and lowering the age of onset of the disease.
Rare deterministic genes are those that directly cause a disease, guaranteeing that anyone who inherits them will develop the disorder. In the case of Alzheimer’s disease, such genes are found in less than 1% of cases and are usually associated with early-onset Alzheimer’s disease. These include mutations in the APP, PSEN1 or PSEN2 genes. In contrast, most cases of Alzheimer’s disease are linked to risk genes. These genes make an individual more susceptible to the disease, but do not guarantee that it will occur. For example, the APOE ε4 gene variant is the most significant genetic risk factor for late-onset Alzheimer’s disease, increasing the risk and lowering the age of onset of the disease.