Have you ever wondered what causes the memory lapses in a person with Alzheimer’s Disease? Someone did the math for you. Many genetic studies have been conducted involving over ten thousand pairs of twins raised apart and they consistently showed that genetic differences account for about half of the variation in mental abilities.
Well, now you know whom to blame when you never fare well enough in your math exam while others sail through.
Your genes determine how strong or weak your memory is, and how it evolves through your lifetime. They also determine if you have the chances of developing memory-related illnesses such as Alzheimer’s disease and Depression.
In the quest for the genetic code, numerous genes have been identified over the past decade that have been closely tied with memory and diseases that affect memory such as Alzheimer’s and Depression. Many more are yet to be discovered. Of the genes that are discovered, there are five whose absence or unaltered form is vital to a good memory.
The Five Genes responsible for Alzheimer’s Disease are as follows:
- Apolipoprotein (ApoE) Gene: ApoE e4, a variant of the ApoE gene is known as the ‘susceptibility gene’ and rightly so, as it predisposes the person with the gene to sporadic or late-onset familial Alzheimer’s disease, without actually causing the disease itself. Another variant of the e4 causes higher absorption of cholesterol and the ensuing risk of heart attack. ApoE e2 is interestingly just the opposite of e4 and signifies a reduced risk of Alzheimer’s disease. ApoE e3 is also not associated with a higher risk of Alzheimer’s disease.
- Presenilin 1 and Presenilin 2 Genes: Presenilin 1 and Presenilin 2 genes are responsible for early onset familial Alzheimer’s disease, a relatively rare form of memory disorder afflicting those younger than 60 years of age. The destructive plaques that are indicative of Alzheimer’s disease are fuelled by these two genes. Of the two, Presenilin 1 is more common, being present in nearly half of patients with early onset Alzheimer’s Disease.
- Amyloid precursor protein Gene: Like the presenilin genes, the mutated forms of amyloid precursor protein gene predispose an individual to early onset Alzheimer’s disease.
- Brain-derived neurotropic factor (BDNF): BDNF is a gene that directs the production ofbrain growth factor, a chemical that ﬂows to the synapses, or spaces, between neurons to help relay messages. People with the ‘met’ variant of the gene have weaker episodic memory compared with those who have the ‘val’ variant.
We have much left to desire when it comes to knowledge about genes and Alzheimer’s disease. In addition to these genes that predispose a person to Alzheimer’s disease, there are genes that are deemed “protective” against Alzheimer’s, but much remains to be known about them and how they work.
Final Words on Genes and Alzheimer’s Disease
A better understanding of these genes would do good to help us understand how they work and much more so, how to prevent and treat Alzheimer’s disease.