A Colombian family with more than six thousand living family members was the focus of researchers at several institutes in the U.S. and Columbia.
According to an article published by the National Institutes of Health, family members with a mutation known as Presenilin 1 have almost a 100% chance of contracting early-onset Alzheimer’s disease, a rare disease.
APOE3ch May be The Key to Developing A Treatment
It is not often someone can beat the odds when it comes to genetic destiny, but one family member did.
The unique case involved a member of the family who carried the Presenilin 1 gene that causes early-onset Alzheimer’s. In this woman’s case, however, she carried two copies of the APOE3ch gene variant and did not show signs of Alzheimer’s for almost thirty years. APOE3ch did, in fact, cause early-onset Alzheimer’s in other members of her family generally beginning around age forty.
The case study was published in Nature Medicine. It was suggested that the two copies of the APOE3ch variant the woman carried may have offered her protection against Alzheimer’s.
Information about the APOE gene may be found here.
Researchers were equally surprised when they discovered that she had only a minor problem with neurodegeneration. She did, however, carry one of the more significant characteristics of Alzheimer’s, which was amyloid protein deposits in her brain.
A second characteristic that is familiar to researchers is tau tangles, which are associated with memory and cognition. The woman being studied exhibited a fairly low amount of tau tangles.
Plaque, the Hallmark of Alzheimer’s Disease
Excess amounts of amyloid-beta peptide, a toxic protein fragment, are produced by mutations of three genes: amyloid precursor protein, Presenilin 1 and Presenilin 2.
These excessive amounts accumulate in the brain, forming amyloid plaques, the hallmark of Alzheimer’s disease. As the plaques continue to form in the brain, malfunctions occur, causing tau proteins to bind together forming neurofibrillary tangles. It is these tangles that are believed to be the cause of most abnormal brain functions seen in Alzheimer’s patients.
Not all people with early-onset Alzheimer’s disease harbor these three mutations. This gives rise to the premise that there may be different genetic mutations or factors that have yet to be identified.
Information about topics for aging is available through the National Institute on Aging website.