Daily Archives: April 15, 2014

PUBLIC RELEASE DATE:

14-Apr-2014

Contact: Bruce Goldman goldmanb@stanford.edu 650-725-2106 Stanford University Medical Center

STANFORD, Calif. Carrying a copy of a gene variant called ApoE4 confers a substantially greater risk for Alzheimer's disease on women than it does on men, according to a new study by researchers at the Stanford University School of Medicine.

The scientists arrived at their findings by analyzing data on large numbers of older individuals who were tracked over time and noting whether they had progressed from good health to mild cognitive impairment from which most move on to develop Alzheimer's disease within a few years or to Alzheimer's disease itself.

The discovery holds implications for genetic counselors, clinicians and individual patients, as well as for clinical-trial designers. It could also help shed light on the underlying causes of Alzheimer's disease, a progressive neurological syndrome that robs its victims of their memory and ability to reason. Its incidence increases exponentially after age 65. An estimated one in every eight people past that age in the United States has Alzheimer's. Experts project that by mid-century, the number of Americans with Alzheimer's will more than double from the current estimate of 5-6 million.

According to the Alzheimer's Association, it is already the nation's most expensive disease, costing more than $200 million annually. (The epidemiology of mild cognitive impairment is fuzzier, but this gateway syndrome is clearly more widespread than Alzheimer's.)

The number of women with Alzheimer's far exceeds that of men with the condition. That's partly because women on average live longer than men. But greater longevity explains only part of women's increased susceptibility to Alzheimer's. "Even after correcting for age, women appear to be at greater risk," said Michael Greicius, MD, assistant professor of neurology and neurological sciences and medical director of the Stanford Center for Memory Disorders.

Greicius was the senior author of a study, to be published April 14 in the Annals of Neurology, in which he and his colleagues analyzed records on more than 8,000 people, most of them older than 60, who have been monitored over time at any one of about 30 Alzheimer's centers nationwide. Postdoctoral scholar Andre Altmann, PhD, was the lead author.

The records were stored in two large, publicly available repositories. In one, the researchers analyzed clinical assessments of 5,000 people whose test results were normal at the outset and 2,200 people who had initially showed signs of mild cognitive impairment. In both groups, being an ApoE4 carrier increased the likelihood of Alzheimer's disease, as expected. But a closer look revealed that among those who initially tested normal, this increased risk was only marginal for men, whereas women who carried the ApoE4 variant had close to twice the likelihood of progressing to mild cognitive impairment or Alzheimer's disease as those who didn't.

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Gene variant puts women at higher risk of Alzheimer's than it does men, study finds

PUBLIC RELEASE DATE:

14-Apr-2014

Contact: Krista Conger kristac@stanford.edu 650-725-5371 Stanford University Medical Center

STANFORD, Calif. As many as 10 percent of women with a personal or family history of breast or ovarian cancer have at least one genetic mutation that, if known, would prompt their doctors to recommend changes in their care, according to a new study by researchers at the Stanford University School of Medicine.

The women in the study did not have mutations in BRCA1 or BRCA2 (mutations in these genes are strongly associated with hereditary breast and ovarian cancer), but they did have mutations in other cancer-associated genes.

The study was conducted using what's known as a multiple-gene panel to quickly and cheaply sequence just a few possible genetic culprits selected by researchers based on what is known about a disease. Although such panels are becoming widely clinically available, it's not been clear whether their use can help patients or affect medical recommendations.

"Although whole-genome sequencing can clearly be useful under the right conditions, it may be premature to consider doing on everyone," said James Ford, MD, who directs Stanford's Clinical Cancer Genetics Program. "Gene panels offer a middle ground between sequencing just a single gene like BRCA1 that we are certain is involved in disease risk, and sequencing every gene in the genome. It's a focused approach that should allow us to capture the most relevant information."

Ford, an associate professor of medicine and of genetics, is the senior author of the study, which will be published April 14 in the Journal of Clinical Oncology. Allison Kurian, MD, assistant professor of medicine and of health research and policy, and associate director of the Clinical Cancer Genetics Program, is the study's lead author.

Ford was a co-author on a recent paper in the in The Journal of the American Medical Association that highlighted the challenges and opportunities of making whole-genome sequencing clinically available for seemingly healthy people. Although that study showed that whole-genome sequencing can be potentially life-saving, the challenges involved in sequencing the billions of nucleotides that make up all of a person's DNA, and then translating the results into clinical care recommendations, is significant.

"This study indicates that using gene panels to screen for potentially harmful variants can be clinically useful in certain groups of patients," said Kurian. "It also shows that patients, some of whom had given blood samples for research as many as 10 years earlier, are willing and interested to receive this type of follow-up information and to incorporate it into their health care plans."

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Gene panels may be useful, cheaper alternative to whole-genome sequencing, study finds