New Alzheimer’s Risk Gene Discovered

Scientists have discovered a link between Alzheimer’s disease and a rare gene mutation associated with inflammation. The gene variant called TREM2 affects the central nervous system and has been shown to control inflammation, which has been related to Alzheimer’s and cognitive impairment.

The findings of several independent studies conducted at deCode Genetics and John Hardy of University College London have been published Wednesday in The New England Journal of Medicine.

Compared to ApoE4, by far the most recognized genetic link to late-onset Alzheimer’s disease (LOAD), which afflicts older seniors, TREM2 is rare. ApoE4 is ten times more common than TREM2 and shows up in 40 percent of patients diagnosed with LOAD. TREM2 has demonstrated a fourfold increase in the risk of developing Alzheimer’s.

In addition to depriving people of their memories, Alzheimer’s is a debilitating disease that affects balance, gait and overall mobility. 5 million Americans now suffer from Alzheimer’s, costing the country more than $170 billion in treatment annually.

Until now, treatment of the disease has largely and unsuccessfully focused on removing that plaque, called beta amyloid protein, that builds up on the brains of Alzheimer’s patients. No drugs have shown any significant gain in people with mild to moderate dementia.

Inflammation is a response often associated with microglia cells, which perform the function of cleaning up certain tissues. TREM2 affects a protein deposited on the surface of these microglia cells.

By changing the function of the microglia cells, the gene mutation may also affect the ability of the brain to cope with the toxic proteins from beta amyloid. TREM2 is probably changing the way brain cells operate. It was also found to be a predictor of poor cognitive performance in older people not diagnosed with Alzheimer’s.

Scientists involved in the study consider TREM2 a universal trait of the disease that could play a role in both early-onset and late-onset Alzheimer’s.

Researchers now have a new promising avenue of pursuit to fight one of the world’s most debilitating diseases, and new impetus to explore many other potential genetic links to Alzheimer’s disease. Drug companies can now focus on the development of new drugs that target microglial cells and TREM2.