What Genes are Involved in Alzheimer’s Disease (AD)?

It is important to note that while certain genes are associated with an increased risk of developing Alzheimer’s disease, having one or more of these gene variants does not guarantee that someone will develop the disease. Other factors, such as age, lifestyle, and environmental factors, also play a role in the development of Alzheimer’s disease.

Several genes have been identified that are associated with an increased risk of developing Alzheimer’s disease. The most well-known of these genes are:

1. APOE: The APOE gene codes for a protein that helps carry cholesterol in the blood. There are three common versions, or alleles, of the APOE gene: APOE2, APOE3, and APOE4. People who inherit one copy of the APOE4 allele have an increased risk of developing Alzheimer’s disease, and those who inherit two copies have an even higher risk.
2. APP, PSEN1, and PSEN2: These genes are involved in the making of a protein called amyloid beta, which forms the sticky plaques that are a hallmark of Alzheimer’s disease. Changes in these genes can cause abnormal forms of amyloid beta, which can build up in the brain and cause damage.
3. TREM2: The TREM2 gene codes for a protein that helps to regulate the immune system in the brain. Variants in this gene have been linked to an increased risk of developing Alzheimer’s disease.

Genetic testing can help to identify individuals who may be at increased risk for Alzheimer’s disease due to these genetic factors.

Other genetic variants that have been identified as risk factors associated with an increased risk of developing Alzheimer’s disease include:

1. Clusterin (CLU): This gene codes for a protein that is involved in the formation of amyloid plaques in the brain, a hallmark of Alzheimer’s disease. Variants in the CLU gene have been associated with an increased risk of developing Alzheimer’s disease.
2. PICALM: This gene codes for a protein that is involved in the transport of amyloid precursor protein (APP), a protein that is involved in the production of amyloid plaques.
3. CR1: This gene codes for a protein that is involved in the immune system and is thought to play a role in clearing amyloid plaques from the brain.

Other genetic risk factors that have been identified for Alzheimer’s disease include:

1. Variants in the SORL1 gene: SORL1 codes for a protein that plays a role in the transport and processing of amyloid precursor protein (APP), a protein that is involved in the production of amyloid plaques in the brain.
2. Variants in the ABCA7 gene: ABCA7 codes for a protein that is involved in the transport of lipids, including the lipids that are involved in the formation of amyloid plaques.

What are known protector factor genes that reduce risk of AD?

In the context of Alzheimer’s disease, protective factor genes are those that have been found to reduce the risk of developing the disease or to delay its onset.

Some examples of protective factor genes that have been identified for Alzheimer’s disease include:

1. The APOE ε2 allele: As mentioned earlier, the APOE ε4 allele is a well-established genetic risk factor for Alzheimer’s disease, while inheriting one copy of the APOE ε2 allele has been shown to be protective against the disease.
2. The SIRT1 gene: SIRT1 codes for a protein that is involved in the regulation of cellular processes such as DNA repair and cell survival. Variants in the SIRT1 gene have been associated with a reduced risk of developing Alzheimer’s disease.
3. The BDNF gene: BDNF codes for a protein that is involved in the growth and survival of neurons in the brain.
4. The KIBRA gene: KIBRA codes for a protein that is involved in the formation and function of synapses, the connections between neurons in the brain.

It is important to note that having protective factor genes does not guarantee that an individual will not develop Alzheimer’s disease, as other factors such as lifestyle and environmental factors also play a role in the development of the disease. However, identifying protective factor genes can provide insights into the underlying biological processes that are involved in the development of the disease and may lead to the development of new prevention or treatment strategies.