By Ralph Sanchez, MTCM, CNS, D.Hom.
Recently (11/13), a rare variant of the TREM2 gene, designated as R47H, was shown to increase the risk of developing Alzheimer’s disease. Individuals with the variant may be up to 3 to 5 times more likely to develop Late Onset Alzheimer’s disease (LOAD). This susceptibility to LOAD in R47H genotypes, is similar to that conferred by the ApoE4 gene.
The TREM2 gene is involved in immune regulatory processes in the brain and the R47H mutation impairs the gene’s ability to contain inflammation. One of the roles of the TREM2 gene is to aid the brain in efficiently eliminating beta amyloid; the toxic protein that forms plaques associated with Alzheimer’s disease.
PREMIUM CONTENT: Mild Cognitive Impairment (MCI)–Telltale Signs That You May Be At Increased Risk for Dementia or Alzheimer’s Disease
Long before a diagnosis of Dementia or Alzheimers disease (AD) is given, brain damage is occurring that leads to, and reflects the gradual downward spiral of mental decline that typifies AD. A cluster of signs that define Mild Cognitive Impairment (MCI), especially memory loss and forgetfulness, may be the early warning indicators that you are at risk for developing AD. If you can visualize a spectrum whereby healthy brain/cognitive function in an individual is on one side of the spectrum, and AD is on the opposite side, MCI would be inching ever so close to the AD side of the spectrum.
Genetic risk factors to Late Onset Alzheimer’s Disease (LOAD) are significant. A recent study of nearly 12,000 Swedish twin pairs, age 65 and older, determined that 58% to 79% of Alzheimer’s risk is genetic (1). This study showed that in male identical twins, when one brother had Alzheimer’s disease, the other developed the disease 45% of the time. In female identical twins, when one sister had Alzheimer’s disease, the other developed the disease 60% of the time. While this study did not delve into specific gene influences in LOAD, numerous studies have identified Apolipoprotein E4 (ApoE4), as a prominent genetic risk factor for LOAD. About 25% of the population has one copy of the ApoE4 gene and individuals with the the ApoE4 gene are estimated to make up approximately 40%-80% of the Alzheimer’s disease population. (2)