A protein commonly found in the brains of Alzheimers patients has been discovered in the spinal fluid of people without dementia whose close relatives were diagnosed with the disease, according to a study led by Duke University researchers.
The researchers also found changes in the Alzheimer's-linked APOE gene and evidence of other unidentified genetic factors to be overrepresented in participants with a family history of the disease. The findings could help lay the groundwork for development of early-detection tools, said Erika Lampert, a Duke researcher involved in the project.
Its possible that these changes are among the reasons people with a family history of Alzheimers are more likely to get Alzheimers, Lampert said.
People with a close family history of Alzheimers such as a brother, sister or parent have a two- to four-times greater risk of developing it themselves.
The study, published last week in the online journal PLOS ONE, involved 257 people age 55 to 89, all of whom had average memory functions or were considered mildly forgetful, said P. Murali Doraiswamy, Duke professor of psychiatry and medicine and senior author of the study.
Each person in the study underwent cognitive assessments, as well as biological tests. Researchers found that about 50 percent of healthy people with a close family connection to Alzheimers could be considered to have early signs of the disease, compared to only about 20 percent of people without a family history.
Memory loss significant enough to disrupt daily activities is a primary symptom of Alzheimers, according to the Alzheimers Association. About 25 million people around the world have Alzheimers disease a number that is expected to grow as the population ages. There is no cure.
Common genetic variations explains about 50 percent of the heritability of Alzheimers, but other genetic factors influencing the disease remain unknown.
So far we have been looking for genetic factors with big effects, but there might turn out to be a number of genes involved, Doraiswamy said.
The amino acid found in the subjects spinal fluid is known as Amyloid beta or Abeta, a component of the plaque build up found in the brains of people with Alzheimers disease.
Doraiswamy said people who have Alzheimers in the family may want to consider volunteering for research studies to enhance scientific knowledge of the illness and also to reassure themselves about their own cognitive performance.
If you want to help scientists make advances in the field, you could ... volunteer as a subject in research studies that involve regular testing of memory, he said. Thats also a way to get reassurance that your memory is normal.