Category Archives: Genetic Medicine

Published: March. 29, 2012 at 11:18 PM

DALLAS, March 29 (UPI) -- U.S. researchers say they have developed a lifesaving genetic screening program for families at high risk of contracting colorectal cancer.

Dr. Samir Gupta, assistant professor of internal medicine at the University of Texas Southwestern in Dallas, who is also head of the high-risk colorectal cancer clinic, said colorectal cancer is the second-leading killer after lung cancer -- and while hereditary colorectal cancer is rare, its family impact can be widespread.

Cancer tends to develop rapidly in those with Lynch syndrome, one of the more common inherited conditions. Lynch syndrome accounts for 3 percent to 5 percent of all colon cancers, and often is undiagnosed until the disease is advanced.

Families that have Lynch syndrome usually have more cases of colon cancer than would typically be expected, and at an earlier ages, than in the general population.

Gupta said doctors screen the tumors of colorectal cancer patients younger than age 70 and uterine cancer patients younger than age 55 to determine whether there is a high risk of a genetic cancer predisposition. If so, patients are encouraged to bring in as many family members as possible for testing, Gupta said.

"If we can bring in family members, we have a chance to catch their colon cancer early and even prevent it," Gupta said in a statement.

Patients with Lynch syndrome have an 80 percent risk of contracting colorectal cancer and as much as a 60 percent risk for uterine cancer, and higher than average risks for other cancer types, Gupta added.

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Genetic screenings detect at-risk families

Editor's Choice Academic Journal Main Category: Cardiovascular / Cardiology Also Included In: Heart Disease;Genetics Article Date: 30 Mar 2012 - 8:00 PDT

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Following PCI, the standard care for patients commonly consists of aspirin and clopidogrel to reduce the risk of blood clot formation, however, this dual antiplatelet therapy results in many patients becoming vulnerable to major adverse cardiovascular events.

This persistent vulnerability is linked to elevated on-treatment platelet reactivity, which can lead to a sudden blockage in the stents that can cause heart attacks or death. The characteristics of elevated on-treatment platelet reactivity are inadequate inhibition of the platelet PsY12 receptor following clopidogrel treatment.

According to scientists, numerous clinical variables have been implicated, however, the strongest predictor is the loss-of-function CYP2C19*2 allele (rs4244285), which is a common genetic variant that occurs in almost 30% of western Europeans and in about 50% of Asians.

Two unique P2Y12 inhibitors are prasugrel and ticagrelor, which compared with clopidogrel provide a more potent platelet inhibition. Although both drugs reduce major adverse cardiovascular events following acute coronary syndrome, they are also linked to higher complications in terms of bleeding. The researchers point out that retrospective genetic studies demonstrated that both, prasugrel and ticagrelor remained unaffected by the CYP2C19*2 allele. According to the authors, personalization of dual antiplatelet therapy after PCI could successfully minimize major adverse cardiovascular and adverse bleeding events if CYP2C19*2 carrier status could be identified in the future.

Spartan Biosciences in Ottawa, ON, Canada, has developed Spartan RX CYP2C19 as a point-of-care genetic test for the CYP2C19*2 allele that is performed with a buccal swab, which enables health-care personnel with no previous training in genetic laboratory techniques to undertake genotyping at the patient's bedside.

The researchers decided to evaluate the clinical feasibility and pharmacodynamic efficacy of personalized dual antiplatelet therapy in patients who receive PCI treatment for acute coronary syndrome and stable coronary artery disease.

The standard care for these patients is a medical regimen of aspirin and clopidogrel, however, the new genetic test means that physicians can personalize the patient's therapy and select whether they should opt to administer a more potent anti-platelet drug like prasugrel to those patients who have a high risk of failing treatment with clopidogrel.

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Using Antiplatelet Therapy After Coronary Interventions - Study

Newswise The first atlas of the surface of the human brain based upon genetic information has been produced by a national team of scientists, led by researchers at the University of California, San Diego School of Medicine and the VA San Diego Healthcare System. The work is published in the March 30 issue of the journal Science.

The atlas reveals that the cerebral cortex the sheet of neural tissue enveloping the brain is roughly divided into genetic divisions that differ from other brain maps based on physiology or function. The genetic atlas provides scientists with a new tool for studying and explaining how the brain works, particularly the involvement of genes.

Genetics are important to understanding all kinds of biological phenomena, said William S. Kremen, PhD, professor of psychiatry at the UC San Diego School of Medicine and co-senior author with Anders M. Dale, PhD, professor of radiology, neurosciences, and psychiatry, also at the UC San Diego School of Medicine.

According to Chi-Hua Chen, PhD, first author and a postdoctoral fellow in the UC San Diego Department of Psychiatry, If we can understand the genetic underpinnings of the brain, we can get a better idea of how it develops and works, information we can then use to ultimately improve treatments for diseases and disorders.

The human cerebral cortex, characterized by distinctive twisting folds and fissures called sulci, is just 0.08 to 0.16 inches thick, but contains multiple layers of interconnected neurons with key roles in memory, attention, language, cognition and consciousness.

Other atlases have mapped the brain by cytoarchitecture differences in tissues or function. The new map is based entirely upon genetic information derived from magnetic resonance imaging (MRI) of 406 adult twins participating in the Vietnam Era Twin Registry (VETSA), an ongoing longitudinal study of cognitive aging supported in part by grants from the National Institutes of Health (NIH). It follows a related study published last year by Kremen, Dale and colleagues that affirmed the human cortical regionalization is similar to and consistent with patterns found in other mammals, evidence of a common conservation mechanism in evolution.

We are excited by the development of this new atlas, which we hope will help us understand aging-related changes in brain structure and cognitive function now occurring in the VETSA participants, said Jonathan W. King, PhD, of the National Institute on Aging, part of the NIH.

The atlas plots genetic correlations between different points on the cortical surface of the twins brains. The correlations represent shared genetic influences and reveal that genetic brain divisions do not map one-to-one with traditional brain divisions that are based on structure and function. Yet, the pattern of this genetic map still suggests that it is neuroanatomically meaningful, said Kremen.

Kremen said the genetic brain atlas may be especially useful for scientists who employ genome-wide association studies, a relatively new tool that looks for common genetic variants in people that may be associated with a particular trait, condition or disease.

Co-authors of the study are Wes Thompson, Matthew S. Panizzon, UCSD Department of Psychiatry; E.D. Gutierrez, UCSD Department of Cognitive Science; Terry L. Jernigan, UCSD departments of Psychiatry and Cognitive Science; Lisa T. Eyler and Amy J. Jak, UCSD Department of Psychiatry and VA San Diego Healthcare System; Christine Fennema-Notestine, UCSD department of Psychiatry and Radiology; Michael C. Neale, Virginia Commonwealth University; Carol E. Franz, UCSD Department of Psychiatry and UCSD Center for Behavioral Genomics; Michael J. Lyons and Michael D. Grant, Boston University; Bruce Fischl, Harvard Medical School and Massachusetts General Hospital; Larry J. Seidman, Harvard Medical School; and Ming T. Tsuang, UCSD Department of Psychiatry, VA San Diego Healthcare System, UCSD Center for Behavioral Genomics.

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How Genes Organize the Surface of the Brain

Public release date: 29-Mar-2012 [ | E-mail | Share ]

Contact: Elizabeth Lynch elynch@marchofdimes.com 914-997-4286 March of Dimes Foundation

CHARLOTTE, NC -- A long-time clinician and researcher on Marfan syndrome who helped identify the syndrome's genetic cause and a potential treatment will be honored by the March of Dimes.

Harry (Hal) Dietz, MD, the Victor A. McKusick Professor of Institute of Genetic Medicine and Professor of Pediatrics, at Johns Hopkins University School of Medicine and Howard Hughes Medical Institute Investigator, will receive the March of Dimes/Colonel Harland Sanders Award for Lifetime Achievement in the field of genetic sciences. Dr. Joe Leigh Simpson, senior vice president for Research and Global Programs of the March of Dimes, will present the award to Dr. Dietz today during the annual Clinical Genetics Meeting of the American College of Medical Genetics at Charlotte Convention Center.

Marfan syndrome is an inherited connective tissue disorder that affects about 1 in 5,000 people. The syndrome is caused by a genetic defect which causes overgrowth of the body's long bones and affects the tissue that strengthens the body's structures, including the skeletal system, cardiovascular system, eyes, and skin.

Those who have the syndrome tend to be tall with arms and legs much longer than expected for their height. Also, in those with Marfan syndrome, the aorta, the main blood vessel that takes blood from the heart to the body, may stretch or become weak, leading to an aneurysm.

In 1991, Dr. Dietz was a member of the team that identified the gene for Marfan syndrome. In 2006, his team's research showed that an FDA-approved high blood pressure medication, losartan, prevented and reversed aortic enlargement in mice with Marfan syndrome.

Dr. Dietz received his medical degree from the State University of New York Upstate Medical Center in 1984. He joined Johns Hopkins University Hospital in 1984 as a pediatric resident, became a Fellow in Cardiology there 1988, went on to pursue his post doctorate work at John Hopkins as wells and continues his research there today.

He was named the Richard Starr Ross Research Scholar, he received the Richard D. Rowe Award for outstanding research in Pediatric Cardiology, the Young Investigator Award, Society for Pediatric Research, and the Antoine Marfan Award, from the National Marfan Foundation. Dr. Dietz also is a member of the Board of Governors, National Human Genome Research Institute, a member of the American Society for Pediatric Research and the American Society for Clinical Investigation.

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Researcher who identifed genetic cause and possible treatment for Marfan syndrome honored

Dr. Derek So and Dr. Jason Roberts. (CNW Group/OTTAWA HEART INSTITUTE, UNIVERSITY OF OTTAWA)

OTTAWA, March 29, 2012 /CNW/ - Developed in Canada and conducted by researchers from the University of Ottawa Heart Institute (UOHI), in partnership with Spartan Bioscience, the world's first bedside genetic test has received acknowledgment by The Lancet, the world's leading general medical journal.

The article Point-of-care genetic testing for personalisation of antiplatelet treatment (RAPID GENE): a prospective, randomised, proof-of-concept trial, reports on the use of a simple cheek swab test, the Spartan RX CYP2C19, performed by nurses at the patient's bedside. This revolutionary technology allows doctors to rapidly identify patients with a genetic variant known as CYP2C19*2. Cardiac stent patients with this variant are at risk of reacting poorly to standard anti-platelet therapy with Plavix (clopidogrel).

The study demonstrated that tailored drug treatment therapy made possible by the genetic testing successfully protected all of the patients with the at-risk genetic variant from subsequent adverse events, while 30 per cent of patients treated with standard therapy did not receive adequate protection.

"For the first time in medicine, nurses were able to perform DNA testing at the patient's bedside. This is a significant step towards the vision of personalized medicine," said Dr. Derek So, Interventional Cardiologist at the University of Ottawa Heart Institute (UOHI), and principal investigator of the RAPID GENE study.

Study Details The RAPID GENE study enrolled 200 patients who were being treated with cardiac stenting for an acute coronary syndrome or stable angina. Patients were randomized to a treatment strategy of rapid point-of-care genotyping and Effient (prasugrel) for CYP2C19*2 carriers, or to standard therapy with Plavix (clopidogrel). The Spartan RX CYP2C19 bedside DNA test was performed by nurses who received a 30-minute training session, but had no prior laboratory training. The test had a sensitivity of 100% and a specificity of 99.4% compared with DNA sequencing. For CYP2C19*2 carriers, treatment with prasugrel completely eliminated High on-treatment Platelet Reactivity (HPR). HPR is a marker for patients at risk of complications after stenting. In contrast, 30.4% of carriers receiving clopidogrel had HPR at 1 week.

About UOHI As Canada's largest and foremost cardiovascular health centre, the University of Ottawa Heart Institute is dedicated to understanding, treating, and preventing heart disease. We deliver high-tech care with a personal touch, shape the way cardiovascular medicine is practiced, and revolutionize cardiac treatment and understanding. We build knowledge through research and translate discoveries into advanced care. We serve the local, national, and international communities as we pioneer a new era in heart health.

Image with caption: "Dr. Derek So and Dr. Jason Roberts. (CNW Group/OTTAWA HEART INSTITUTE, UNIVERSITY OF OTTAWA)". Image available at: http://photos.newswire.ca/images/download/20120329_C8698_PHOTO_EN_11670.jpg

INFORMATION AND INTERVIEWS Vincent Lamontagne Senior Manager Public Affairs University of Ottawa Heart Institute 613-761-4427 613-899-6760 (cell) vlamontagne@ottawaheart.ca

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World's first bedside genetic test gets green light by prestigious medical publication

Public release date: 28-Mar-2012 [ | E-mail | Share ]

Contact: Raymond MacDougall macdougallr@mail.nih.gov 301-402-0911 NIH/National Human Genome Research Institute

Farmers in the highlands of southern Ethiopia scratch out a subsistence living from the region's volcanic red clay. The soil supports the farms, but fine-grained, volcanic rock particles in the dirt threaten the farmers and their families. Continual exposure of bare feet to the volcanic soil causes 1 in 20 people to develop a painful inflammation of the lower extremities that, over time, leads to foot disfigurement. Doctors call it podoconiosis. The locals call it mossy foot. And those affected suffer social stigma as well as debilitating discomfort.

Now, researchers think they know why some 4 million people in at least 10 countries worldwide develop this incapacitating condition. One-fifth carry genetic variants that cause their immune system to react to the volcanic dust. This disease-producing response, triggered by exposure from the lack of shoes, provides a dramatic example of the interaction between genes and the environment.

Writing in the March 29, 2012 New England Journal of Medicine, an international team that includes researchers from the National Human Genome Research Institute (NHGRI), part of the National Institutes of Health, describes the genetic link that turns dirt into a toxin.

"This study draws attention to a neglected tropical disease with a devastating impact on poor people and their communities," said NHGRI Scientific Director Dan Kastner, M.D., Ph.D. "It demonstrates the global reach of genomics research into the lives of people in parts of the world where endemic diseases very often go unchecked."

Doctors have known for a long time that podoconiosis runs in families and that continual exposure to volcanic soil triggers it. Wearing shoes and socks, or even washing off the dirt, prevents the condition. But doctors have been perplexed that only some people develop the disease, while others with the same environmental exposure are spared.

To sort this out, the international collaborators conducted a genome-wide association studyor GWASanalyzing DNA from 194 volunteers from the Ethiopian highlands affected by podoconiosis, along with DNA from another 203 unaffected individuals from the same region. The researchers collaborated with field workers from the non-profit Mossy Foot Treatment and Prevention Association in southern Ethiopia to collect the data and samples.

The researchers generated a dataset from study-participant DNA, screening more than 550,000 single-nucleotide polymorphisms (SNPs), which are sites in an individual's DNA that contain a different chemical base when compared to a standard reference human genome sequence. They found significant podoconiosis association for eight SNPs within or nearby a stretch of DNA on chromosome 6, called the HLA class II locus.

The researchers performed a second validation step, called a family-based association study, using DNA samples from 202 sets of child-parent trios from affected families. The researchers detected six SNPs that showed significant associationthose that mapped to HLA class II region genes and most strongly associated with podoconiosis in the GWAS, validating the GWAS results.

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Researchers identify genetic basis of tropical foot and leg lymphedema