In February 2020, Epigenetics published results of a study reporting that researchers have found an early sign of Alzheimer’s disease in DNA modification (methylation) that had been overlooked.
Patients who have the inherited form of the disease are found to carry mutations in presenilin proteins (PSEN1 and PSEN2).
A chemical alteration in the PSEN1 gene may possibly be a biomarker in the diagnosis of early-onset familial Alzheimer’s disease (EOFAD).
There are over three hundred mutations in the PSEN1, the PSEN2, and the APP genes. These mutations cause increased production of amyloid-beta, a well-known component of amyloid deposits in the brains of Alzheimer’s disease patients.
There has been very little research on the human PSEN1 gene, even though patients exhibited behavior that was altered by the gene.
The current study is the first to demonstrate frequent DNA methylation associated with the PSEN1 gene in these patients.
Previous studies, however, observed the DNA methylation in brain samples of Alzheimer’s disease mouse models. It has also been observed in post-mortem brain tissue and blood samples from patients with late onset.
Methylation is a process whereby an associated gene is suppressed. It is noteworthy that earlier animal studies found that the PSEN1 gene can be suppressed. Researchers have found that this suppression causes a condition much like Azheimer’s disease.
The current thinking is that PSEN1 experiences partial methylation, but maintains a stable condition during embryonic and childhood stages.
About Alzheimer’s Disease (AD)
Alzheimer’s disease affects approximately fifty million people worldwide. Most patients are over sixty years old (late on-set), yet a significant number of people below the age of fifty (early on-set) also develop symptoms.
The disease involves the loss of memory, thought, and learning. It is believed that the numbers as presented represent only a fraction of all cases because the majority of patients have not been diagnosed.
Eventually, the disease progresses to the point that the patient is unable to function. Medications exist that will possibly delay cognitive loss, but only if treatment begins during the early stages of the disease.
About the Human Brain
A healthy human brain holds billions of cells (neurons) that send messages back and forth between various parts of the brain. The brain also sends messages to muscles as well as organs of the body.
Alzheimer’s interferes with these communications. The result is cell death and loss of normal functions.
Results of the Study
The study shows that changes in the methylation status of the PSEN1 gene, a common feature of the disease, have an overall effect on nerve cell degeneration.
It has now been fairly well established that these findings present a new, non-invasive method of diagnosing the disease.