Current tests used to examine whether someone will develop Alzheimer's disease rely on the detection of a certain protein, called Tau, in the central nervous system, floating around in the cerebrospinal fluid. Presence of this biomarker tends to indicate the progression towards the memory robbing disease, yet there is no current way of knowing who will start to express these proteins and become ill years ahead of time.

Researches may have hope for an early test that may indicate who will develop these protein accumulations.  They have identified mutations in certain regions of the genome that influence the levels of protein accumulation.  The research will not only enable healthcare professionals and patients to identify people who are at the most risk for the disease but may lead to understanding the disease and hopefully result in effective treatments.

"Tau is an important biomarker of neurodegeneration in Alzheimer's disease, present as insoluble aggregates in the brain and as soluble protein in the cerebrospinal fluid," explains senior author Dr. Alison Goate, of Washington University School of Medicine in St. Louis. "We have identified several genes that influence the levels of soluble tau in the cerebrospinal fluid, and we show that one of these genes also influences risk for Alzheimer's disease, rate of cognitive decline in Alzheimer's disease, and density of tangle pathology in the brain."

Dr. Goate and her team have performed the most extensive genetic analysis to date, analyzing 1,269 patients, more than three times the number of people than in previous studies.

Another region identified as having genetic mutations predisposing people to Alzheimer's and protein accumulation has previously been implicated in the disease was found in the gene TREM2.  The gene is a receptor on the surface of cells and can influence another gene in the same family named TREML2.

"Interestingly, although these genes are similar, the association of TREM2 and TREML2 with cerebrospinal fluid tau levels were in the opposite direction-one associated with risk for Alzheimer's disease and the other protective," says first author Dr. Carlos Cruchaga, also of Washington University School of Medicine.

Researchers on the team are now pursuing investigations on the effects of the gene mutation on cultured cells and in the nervous system of brains.

"In the longer term, we anticipate that knowledge about the role of these genes in Alzheimer's disease may lead to the identification of new targets from therapies or new animal or cellular models of the disease," says Dr. Goate.

The research begs the question that if there was a test to predict Alzheimer's disease, would you want to know if you carry the mutations?

The research published in the journal Neuron can be found here