Alzheimer’s disease is a progressive neurodegenerative disorder characterized by memory loss, cognitive decline, and behavioral changes. It is the most common form of dementia, affecting millions of people worldwide.

While the exact cause of the disease is unknown, scientists have identified several risk factors, including genetics.

What is the Alzheimer’s Gene?

The Alzheimer’s gene, also known as the APOE gene, provides instructions for making a protein called apolipoprotein E.

This protein plays a crucial role in the metabolism of lipids and cholesterol in the body and is involved in the clearance of beta-amyloid, a protein that accumulates in the brain of Alzheimer’s patients.

There are three different forms of the APOE gene: APOE2, APOE3, and APOE4. The APOE4 variant is associated with an increased risk of developing Alzheimer’s disease.

Individuals who inherit one copy of the APOE4 gene from a parent have a threefold increased risk of developing Alzheimer’s, while those who inherit two copies have a tenfold increased risk.

Can You Be Born with the Alzheimer’s Gene?

The APOE gene is present in every individual, but the specific variant that a person inherits is determined by their parents.

This means that a child can inherit the APOE4 variant from one or both parents, putting them at increased risk of developing Alzheimer’s later in life.

Research has shown that the presence of the APOE4 variant can affect brain development from childhood, even before symptoms of Alzheimer’s appear.

A study published in the Journal of Alzheimer’s Disease found that children with the APOE4 gene had smaller brain volumes and reduced white matter integrity compared to children without the gene variant.

Another study published in Neurology found that young adults with the APOE4 gene had worse cognitive performance and smaller hippocampal volumes (an area of the brain important for memory) compared to those without the gene variant.

How Does the Alzheimer’s Gene Affect Brain Function?

The APOE gene variants are thought to affect brain function through several mechanisms. One is through the accumulation of beta-amyloid protein in the brain.

Individuals with the APOE4 variant have been found to have higher levels of beta-amyloid in the brain, even in early adulthood.

Another mechanism is through the regulation of inflammation in the brain.

Alzheimer’s disease is associated with chronic inflammation, and the APOE gene variants have been found to affect the production of cytokines (proteins involved in inflammation) in the brain.

The APOE gene variants may also affect the clearance of beta-amyloid from the brain. Studies have shown that individuals with the APOE4 variant have a reduced ability to clear beta-amyloid from the brain compared to those with the APOE3 variant.

Can Lifestyle Changes Reduce the Risk of Alzheimer’s?

While the presence of the APOE4 gene variant increases the risk of developing Alzheimer’s disease, it doesn’t mean that a person will definitely develop the disease.

Lifestyle factors such as diet, exercise, and social engagement have been shown to reduce the risk of cognitive decline and dementia.

One study published in The Journal of the Alzheimer’s Association found that individuals with a healthy lifestyle (defined as regular physical activity, healthy diet, non-smoking, moderate alcohol consumption, and cognitive stimulation) had a significantly lower risk of Alzheimer’s disease, regardless of their APOE genotype.

Another study published in PLOS One found that individuals with the APOE4 gene who were physically active had better cognitive performance compared to those with the gene who were sedentary.

Conclusion

The impact of the Alzheimer’s gene can be felt from childhood, affecting brain development and function.

However, the risk of developing Alzheimer’s disease is not predetermined by genetics alone, and lifestyle interventions can significantly reduce the risk of cognitive decline and dementia, even in individuals with the APOE4 gene.