Scientists have found that Alzheimer’s disease could be at work in the brain years before symptoms even show up.

A research team from Indiana University found that a genetic variant that is linked to Alzheimer’s may be causing deposits of plaque in the brain long before tests can verify the presence of the disease, according to a Business Standard report.

For the study, scientists looked at people with significant memory concerns, or older individuals who noticed their memory getting worse lately, but still performed well on standard cognition and memory tests.

The researchers looked at data from 600 participants and compared them to the gene APOE e4, and they found evidence of Alzheimer’s-like pathologies from biomarkers among the APOE e4 carriers.

They found that there were increased levels of amyloid plaque in these patients, which are clumps of protein fragments that are often found in Alzheimer’s patients.

Also, they found decreased levels of the protein precursor of the plaques in the cerebrospinal fluid, which means that the protein was being ‘recuirted” as part of the plaque creation process.

Still, scientists weren’t able to find reduced levels of glucose metabolism or damage to the brain structures that are found in later stages of the disease.

More research will be needed, but these findings provide a lead to scientists hoping to understand the disease better and help spot Alzheimer’s as early as possible so as to begin combating it right away.

The findings were published in the journal Alzheimer’s and Dementia.