Genetics
British team finds two genes for osteoporosis
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British researchers have identified two common genetic mutations that increase the risk of osteoporosis and related bone fractures, according to a study released on Tuesday.
These changes were present in 20 percent of the people studied and highlight the potential role of screening for the bone-thinning disease that mainly affects women after menopause, they reported in The Lancet medical journal.
“Eventually, a panel of genetic markers could be used in addition to environmental risk factors to identify individuals who are most at risk for osteoporotic fractures,” Tim Spector and Brent Richards, researchers at King’s College London wrote.
Tiny magnets used in anti-cancer gene therapy
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Tiny magnets have been used to deliver anti-cancer gene therapy in mice in a development that could make the treatment much more effective, scientists said on Thursday.
The idea behind gene therapy is to replace faulty genes. But the approach has had mixed success because of the difficulty of getting genes to the right part of the body.
One option is to use viruses to carry genes, but this increases the risk of triggering an immune system reaction.
Gene therapy reduces cocaine use in rats
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Researchers at the U.S. Department of Energy’s Brookhaven National Laboratory have shown that increasing the brain level of receptors for dopamine, a pleasure-related chemical, can reduce use of cocaine by 75 percent in rats trained to self-administer it. Earlier research by this team had similar findings for alcohol intake. Treatments that increase levels of these chemicals - dopamine D2 receptors—may prove useful in treating addiction, according to the authors. The study will be published online April 16 and will appear in the July 2008 issue of Synapse.
“By increasing dopamine D2 receptor levels, we saw a dramatic drop in these rats’ interest in cocaine,” said lead author Panayotis (Peter) Thanos, a neuroscientist with Brookhaven Lab and the National Institute on Alcohol Abuse and Alcoholism (NIAAA) Laboratory of Neuroimaging. “This provides new evidence that low levels of dopamine D2 receptors may play an important role in not just alcoholism but in cocaine abuse as well. It also shows a potential direction for addiction therapies.”
HDL-Associated Protein Gene Linked to Heart Disease Risk
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The gene for the HDL-associated protein paraoxonase 1 (PON1) appears to be associated with coronary artery disease and with the risk of developing adverse cardiac events, and variations in both the PON1 gene and its related enzyme activity may increase the risk for cardiovascular disease events, according to a study in the March 19 issue of JAMA, a theme issue on Genetics and Genomics.
Stanley L. Hazen, M.D., Ph.D., of the Cleveland Clinic, presented the findings of the study at a JAMA media briefing at the National Press Club in Washington, D.C.
Despite evidence that PON1 prevents atherosclerosis in animals, a cardio-protective role in humans has not been established. Several studies have suggested that PON1 may have antioxidant and cardio-protective properties, according to background information in the article.
Geneticist First to Connect a Gene Central to Neuron Formation to Autism
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Eli Hatchwell, M.D., Ph.D., Associate Professor of Pathology at Stony Brook University Medical Center, and colleagues have found that a disruption of the Contactin 4 gene on chromosome 3 may be linked to autism spectrum disorder (ASD). What causes ASD, a developmental disorder of the central nervous system, is largely unknown. Dr. Hatchwell’s finding suggests that mutations affecting Contactin 4 may be relevant to ASD pathogenesis, and thus a potential biomarker for some individuals with the disorder. Details of the study are reported in the early online edition of the Journal of Medical Genetics.
According to the Centers for Disease Control and Prevention, the prevalence of ASD in the United States may be as high as 1 in 150 children. The disorder is divided into five subtypes, including autism proper. Pathogenesis of ASD may be environmental and/or biological. Experts suspect that many genes may play a role in the etiology of ASD.
Variations of Stress Response Gene Appear To Be Predictive of Risk of PTSD
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Adults who experienced child abuse and have variations of a gene related to stress response appear to be at greater risk of posttraumatic stress disorder symptoms as adults, according to a study in the March 19 issue of JAMA, a theme issue on Genetics and Genomics.
Rebekah G. Bradley, Ph.D., of the Emory University School of Medicine, Atlanta, presented the findings of the study at a JAMA media briefing at the National Press Club in Washington, D.C.
“Posttraumatic stress disorder (PTSD) is a debilitating stress-related psychiatric disorder, with prevalence rates of at least 7 percent to 8 percent in the U.S. population, and with much higher rates among combat veterans and those living in high-violence areas. Initially viewed as a potentially normative response to traumatic exposure, it became clear that not everyone experiencing trauma develops PTSD. Thus, a central question in research on PTSD is why some individuals are more likely than others to develop the disorder in the face of similar levels of trauma exposure,” the authors write. They add that it is becoming clear that there are critical roles for pre-disposing genetic and environmental influences in determining the psychological risk to the traumatized individual, with child abuse appearing to provide significant risk for the development of PTSD.
Gene Hunters Fine-Tune Marker for Common Obesity Gene
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Genomics researchers, seeking to replicate another group’s discovery of an important gene associated with obesity, have further refined the signal to a particular variant in DNA that may be more helpful in identifying this gene’s role in obesity in various human populations worldwide. The finding suggests that the gene variant, identified in DNA from African American children, may be a tag of an ancient mutation that first arose in Africa, where humans originated.
The research team, led by Struan Grant, Ph.D., and Hakon Hakonarson, M.D., Ph.D., both of the Center for Applied Genomics of The Children’s Hospital of Philadelphia, was studying the FTO gene, identified by a British group in 2007 as raising the risk of adult and childhood obesity. Although environmental influences are certainly important, family studies have indicated that obesity has a genetic component as well.
The research team, from Children’s Hospital and the University of Pennsylvania School of Medicine, reported its findings in the March 12 issue of the journal Public Library of Science ONE.
Researchers Describe Mechanisms by Which Capon Gene Causes Heart Rhythm Disturbances
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A research team from the Cedars-Sinai Heart Institute, Johns Hopkins University and China Medical University and Hospital in Taiwan have described for the first time the mechanisms by which variants of a specific gene, CAPON or NOS1AP, can disrupt normal heart rhythm. Until recently, CAPON was not even suspected of existing in heart tissue or playing a role in heart function.
The study, conducted in guinea pigs, confirms that CAPON naturally exists in the ventricles (pumping chambers) of the heart. The researchers show that CAPON interacts with a signaling molecule (NOS1) in heart muscle to influence signaling pathways and modify cell-to-cell interactions (calcium ion and potassium ion channels) that control electrical currents.
Eduardo Marbán, M.D., Ph.D., director of the Cedars-Sinai Heart Institute, is senior author of an article, published online March 4 in Proceedings of the National Academy of Sciences (Early Edition), that fully describes these events.
Trawl of two groups’ genes shows differences
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A trawl through the genes of white people in Utah and Yoruba people in Nigeria shows a significant number of differences that can explain why some groups respond differently to drugs than others.
The findings also suggest that genes underlie some susceptibility to diseases in a general population, the researchers report in the American Journal of Human Genetics.
What the study does not show, the researchers stress, is that any of these differences are necessarily racial. But they are a first step toward a day when medical care may be tailored not only for individuals, but for entire groups.
U of Minn researchers discover genetic cancer link between humans and dogs
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Cancer researchers at the University of Minnesota and North Carolina State University have found that humans and dogs share more than friendship and companionship – they also share the same genetic basis for certain types of cancer. Furthermore, the researchers say that because of the way the genomes have evolved, getting cancer may be inevitable for some humans and dogs.
Jaime Modiano, V.M.D., Ph.D., University of Minnesota College of Veterinary Medicine and Cancer Center, and Matthew Breen, Ph.D., North Carolina State University’s Center for Comparative Medicine and Translational Research, collaborated on this research study. Their findings are published in the current issue of the journal Chromosome Research, a special edition on comparative cytogenetics and genomics research by scientists from around the world.
Role identified for glaucoma gene and related signaling pathway
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Researchers have found that a gene and a related signaling pathway play a role in the development of glaucoma, which is a common cause of visual impairment and blindness worldwide. The team was led by Alcon Research and included investigators from the University of Iowa and the National Cancer Institute (NCI), part of the National Institutes of Health.
The study, which revealed that over-expression of the gene, sFRP1, elevates pressure in the eye, could help improve glaucoma diagnosis and lead to the development of sight-saving treatments. The study results appeared online Feb. 14 in the Journal of Clinical Investigation.
“The cause of glaucoma and the resulting elevation of intraocular pressure has been poorly understood,” said Abe Clark, Ph.D., Alcon’s vice president of discovery research and head of glaucoma research. “This new discovery may allow researchers to develop therapies to treat the underlying cause of the disease.”
Common gene determines if breast is best
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Breastfeeding is best for your child’s brain as long as a variation of a common gene is present in the baby, researchers say.
Breastfed children with a variant of the FADS2 gene, which is involved in processing fatty acids, score up to seven points higher in IQ tests than bottle-fed children.
But for those children without the variant gene, breastfeeding makes no difference to their intelligence levels.
Tiny gene differences make us who we are
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Scientists have found more than 500 genes that account for variations across human populations including skin colour, height and vulnerability to disease, according to a new study.
By comparing millions of fragments of genetic code from individuals in four groups - from Nigeria, China, Japan and northwest Europe - researchers say that natural selection has played a key role in these differences.
The findings, which are published online ahead of print in the journal Nature Genetics, hold particular promise for understanding the genetic underpinning of certain diseases.
The HLA-DRB1 gene and premature death in rheumatoid arthritis
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People with rheumatoid arthritis (RA), an inflammatory autoimmune disease, tend to die younger and, largely from cardiovascular disease (CVD). One explanation for this increasingly recognized fact is that inflammation promotes atherosclerosis. A marker of inflammation, elevation of the C-reactive protein (CRP) level has been shown to predict CVD in the general population. However, other highly inflammatory diseases—Crohn’s, for example—do not carry the same high risk of premature death from heart disease.
To identify other possible suspects, researchers in the United Kingdom investigated whether genetic variants linked to the likelihood of developing RA might also make patients more likely to die from CVD. Led by Dr. Tracey M. Farragher at the University of Manchester and funded by the Arthritis Research Campaign (arc), the study focused on two genes—HLA-DRB1and PTPN22—and their interactions with known RA risk factors. The evidence, presented in the February 2008 issue of Arthritis & Rheumatism, implicates HLA-DRB1 genotypes, already associated with RA susceptibility and severity, as a predictor of premature death from CVD for inflammatory arthritis patients. For RA patients in particular, having the shared epitope (SE)—a group of HLA-DRB1 alleles with kindred amino acid traits—plus anti-cyclic citrullinated peptide (anti-CCP) antibodies and current smoking is an especially deadly combination.
Study Finds Genetic Link to Herpes Susceptibility
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There’s a high probability that people who are prone to herpes simplex virus (HSV) outbreaks can inherit that susceptibility through their genes, University of Utah researchers report in a new study.
In the Feb. 1 issue of The Journal of Infectious Diseases, the researchers identify a region on the long arm of human chromosome 21 with high odds—at least 1,000-to-1—of being linked to cold sore susceptibility. The researchers further say they pinpointed six specific genes in that chromosomal region as candidates for making people prone to outbreaks of cold sores (also called “fever blisters”). Cold sores occur when the herpes virus reactivates from its quiescent state within the nerve, infecting the lip, nose, or face.
Discovery of the probable link could lead to the development of new drugs that reduce the frequency of herpes outbreaks, according to John D. Kriesel, M.D., the study’s corresponding author and research associate professor in the U School of Medicine’s Division of Infectious Diseases.
