DNA Screening Program Launched for Women
Stroke will be one of several diseases targeted in a major genetic screening program among women, thanks to the new Women's Health Genome Study co-sponsored by the biotechnology company Amgen, Brigham and Women's Hospital in Boston, and the NIH.
Researchers will analyze the DNA of 28,000 women in the Women's Health Study to probe the genetic causes of stroke, myocardial infarction, breast cancer, osteoporosis, and other disorders common in women, to better determine a woman's risk of disease and create effective treatments.
The DNA screening program will specifically evaluate each woman's DNA to ascertain whether similar genetic variations exist in women who have developed stroke and other common diseases.
[Earlier this year, another genetic screening program, an ALS DNA repository consisting of samples from ALS patients and healthy volunteers, termed the ALS Biomaterial and Data Banking initiative, was established at NINDS to study the causes and genetic risk factors for ALS. (See “Innovative Collaboration to Create ALS DNA Bank,” Feb. 21, page 5).]
Neurogeneticists and stroke experts told Neurology Today they were optimistic about the new study. “Once we understand genetic contributions to the risk for stroke, it will be possible to tailor therapies for specific individuals,” said Louis J. Ptacek, MD, who heads the Neurogenetics Laboratory at the University of California-San Francisco and holds the John C. Coleman Distinguished Professorship in Neurodegenerative Diseases.
Daniel Woo, MD, who studies stroke genetics, said it is unlikely that any one study will provide a definite ‘stroke gene.’ But, he said, “A dozen or so genome wide screens could identify a few genes that are replicated in other studies and confirmed through molecular genetic and biochemical studies.” Dr. Woo is the Director of Cerebrovascular Genetics and Associate Professor of Neurology at the University of Cincinnati College of Medicine in Ohio.
In the Women's Health Genome Study, participants were disease-free at the start of the study and have now been followed for more than 12 years, said Paul Ridker, MD, Director of the Center for Cardiovascular Disease Prevention at Brigham and Harvard Medical School, who is leading the study. He added that study results will be posted through the NIH in a public database.
“Public availability of a genome wide screen among women searching for common risks for stroke will be an important first step,” Dr. Woo said.
However, Dr. Ptacek pointed out several study challenges, including the increased chance of identifying false positives within the huge amount of data, which has “remained a serious problem in the field of complex genetics.”
In addition, he continued, “Only in a few cases have actual genetic associations been tied to the specific genetic variant that predisposes to the risk.”
These concerns notwithstanding, Dr. Woo said the screening is an important step in the search for genes that mediate the risk for stroke. “While all study designs have weaknesses, the Women's Health Study has the advantage of avoiding a survival bias in that all cases are enrolled before they have a stroke, whereas case-control studies are limited to subjects who survive a stroke long enough to be enrolled.”