DURHAM, N.C. Duke University Medical Center researchers have identified a group of chromosomal regions that could be responsible for controlling the onset of Alzheimer's or Parkinson's diseases.
The finding is significant because until now, geneticists have focused their attention on identifying individual genes that control the risk of developing a disease. However, the age at which genetically-predisposed individuals develop symptoms of the disease is just as important, says Margaret Pericak-Vance, Ph.D., director of the Center for Human Genetics at Duke and principal investigator of the study.
"Risk is only one mode of genetic expression. Age at onset of disease can also be genetically influenced. Understanding the regulation of onset will open new avenues of research that could one day make it possible to delay onset beyond an individual's normal lifespan," Pericak-Vance said.
The study appears in the April 2002 issue of American Journal of Human Genetics. The research was funded by the National Institutes of Health, the U.S. Public Health Service, the California Department of Health Services, the Fran and Ray Stark Foundation Fund for Alzheimer's Disease Research, the Alzheimer's Disease and Related Disorders Association, and GlaxoSmithKline, Inc.
The Duke research team conducted a genomic screen -- the first ever designed to study age at onset of Alzheimer's and Parkinson's diseases -- of 449 families with multiple family members with Alzheimer's disease and 174 families with multiple family members with Parkinson's disease.
The age of onset of Alzheimer's disease is generally considered the time at which an individual begins to suffer short-term memory loss or disorientation in a manner serious enough to interfere with daily activities. The average age at onset for individuals in the study with Alzheimer's disease was 72.8 years old and 60.1 years old for Parkinson's disease.