Genetics
Researchers to Test First Gene Therapy For Alzheimer’s Patients
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Mount Sinai School of Medicine is one of 12 sites nationwide participating in the first Phase 2 clinical trial to test gene therapy treatment for Alzheimer’s disease. The study is the first multicenter neurosurgical intervention in Alzheimer’s research in the U.S.
The experimental treatment utilizes a viral-based gene transfer system, CERE-110, that makes Nerve Growth Factor (NGF), a naturally occurring protein that helps maintain nerve cell survival in the brain. CERE-110 has been previously studied in animals, where it reversed brain degeneration in aged monkeys and rats. For this study, CERE-110, will be injected by a neurosurgeon directly into the nucleus basalis of Meynert (NBM) of the brain, an area where neuronal death occurs in Alzheimer’s patients.
In animal studies, NGF has been shown to support the survival and function of the neurons that deteriorate in Alzheimer’s patients.
Iron Overload: Treatment for Common Genetic Disorder
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Absorbing and storing too much iron can cause an array of health problems—for starters, joint pain, fatigue, weakness and loss of interest in sex. This condition, called hemochromatosis, is the most common genetic disorder in the United States, most frequently occurring in people of Northern European descent.
The October issue of Mayo Clinic Health Letter provides an overview of hemochromatosis, including its genetic cause, subtle early symptoms, potential health risks and treatment.
When people have hemochromatosis, their bodies absorb and store too much iron from their normal diet. Over decades, the iron levels can build up in various organs, most often the liver and heart. Without treatment, iron levels accumulate to 20 times that of a person without the disorder. The result can be irreversible scarring of the liver (cirrhosis), liver cancer, diabetes, heart failure, heart rhythm problems, arthritis, impotence or darkening of the skin.
New chromosomal abnormality identified in leukemia associated with Down syndrome
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Researchers identified a new chromosomal abnormality in acute lymphoblastic leukemia (ALL) that appears to work in concert with another mutation to give rise to cancer. This latest anomaly is particularly common in children with Down syndrome.
The findings have already resulted in new diagnostic tests and potential tools for tracking a patient’s response to treatment. The research, led by scientists from St. Jude Children’s Research Hospital, also highlights a new potential ALL treatment. Clinicians are already planning trials of an experimental medication targeting one of the altered genes.
This study is published in the October 18 online edition of Nature Genetics.
“A substantial proportion of children with ALL lack one of the previously identified, common chromosomal abnormalities. Also, children with Down syndrome have an increased risk of ALL, but the reasons why are unclear,” said Charles Mullighan, M.D., Ph.D., assistant member in the St. Jude Department of Pathology. Mullighan is senior author of the study, which involved scientists from 10 institutions in the U.S. and Italy. “Our results have provided important data regarding the mechanisms contributing to leukemia in these cases,” he said.
Faulty gene may explain sudden deaths in epilepsy
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A common gene that can cause abnormal heart rhythms can also trigger epileptic seizures in the brain and may explain the sudden, unexplained deaths that often occur in people with epilepsy, U.S. researchers said on Wednesday.
Testing epileptics for a mutation in this gene could give doctors the information they need to prevent some of these deaths, said Dr. Jeffrey Noebels of Baylor College of Medicine, whose study appears in the journal Science Translational Medicine.
Doctors have long known that patients with a mutation in the gene KvLQT1—which makes structures called ion channels that regulate electrical activity in the heart—have a greater risk of sudden death from abnormal heart rhythms.
Scientists find three new gene links to Alzheimer’s
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Scientists have found three new major genetic links to Alzheimer’s, affecting up to 20 percent of people with the brain-wasting disease, and said on Sunday it was the most significant such discovery in 15 years.
Two large studies found that the three new genes join the better-known APOE4 gene as significant risk factors for the most common cause of dementia.
“If we were able to remove the detrimental effects of these genes through treatments, we could reduce the proportion of people developing Alzheimer’s by 20 percent,” Julie Williams, a professor of Neuropsychological Genetics at Britain’s Cardiff University, told a news conference in London.
Diabetes Gene Raises Odds of Lower Birth Weight
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Pediatric researchers have found that a gene previously shown to be involved in the development of type 2 diabetes also predisposes children to having a lower birth weight. The finding sheds light on a possible genetic influence on how prenatal events may set the stage for developing diabetes in later childhood or adulthood.
Researchers from The Children’s Hospital of Philadelphia and the University of Pennsylvania School of Medicine published the study July 10 in the online version of the journal Diabetes.
“It’s a bit unusual to find a gene linked to both prenatal events and to a disease that occurs later in life,” said study leader Struan F.A. Grant, Ph.D., a researcher at the Center for Applied Genomics of The Children’s Hospital of Philadelphia. “This gene variant carries a double whammy, in raising the risk of both lower birth weight and the development of type 2 diabetes in later life.”
Common Cold Virus Efficiently Delivers Corrected Gene to Cystic Fibrosis Cells
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Scientists have worked for 20 years to perfect gene therapy for the treatment of cystic fibrosis, which causes the body to produce dehydrated, thicker-than-normal mucus that clogs the lungs and leads to life threatening infections.
Now University of North Carolina at Chapel Hill School of Medicine scientists have found what may be the most efficient way to deliver a corrected gene to lung cells collected from cystic fibrosis patients. They also showed that it may take this high level of efficiency for cystic fibrosis (CF) patients to see any benefit from gene therapy.
Using parainfluenza virus, one of the viruses that causes common colds, the UNC scientists found that delivery of a corrected version of the CFTR gene to 25 percent of cells grown in a tissue culture model that resembles the lining of the human airways was sufficient to restore normal function back to the tissue.
Genes that influence start of menstruation identified for first time
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Researchers from the Peninsula Medical School, along with collaborators from research institutions across Europe and the United States, have for the first time identified two genes that are involved in determining when girls begin menstruation. The work will be published in Nature Genetics this weekend.
The findings of the study could have ramifications for normal human growth and weight too, because early-age menstruation is also associated with shorter stature and increased body weight. In general, girls who achieve menstruation earlier in life tend to have greater body mass index (BMI) and a higher ratio of fat compared to those who begin menstruation later.
The study carried out an analysis of 17,510 women across eight different international population-based sources. This number included women of European descent who reported the age at which they reached menstruation of between nine and 17 years.
Scientists Find Gene That Modifies Severity of Cystic Fibrosis Lung Disease
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Researchers at Wake Forest University Baptist Medical Center, and colleagues, have identified a gene that modifies the severity of lung disease in people with cystic fibrosis, a lethal genetic condition. The findings open the door to possible new targets for treatment, researchers say.
The study appeared online last week in advance of print publication in Nature. It is the first published study to search the entire genome looking for genes that modify the severity of cystic fibrosis lung disease.
“This is a good example of researchers with different expertise coming together and using the knowledge gained from mapping the human genome to make discoveries that improve our understanding of cystic fibrosis,” said Carl Langefeld, Ph.D., a study co-author and Wake Forest University School of Medicine researcher. “It may also help in the identification of targets for drug development and the development of tools for the earlier diagnosis of individuals with cystic fibrosis who are susceptible to severe lung disease.”
Mouse study sheds light on obesity gene
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German scientists said on Sunday they have shown how a gene long associated with obesity might make people fat, a finding that could lead to new drugs to help control weight.
Mice without the FTO gene did not become obese and had less fat tissue overall because they burned off more calories even though they moved less and ate more, according to the study published in the journal Nature.
FTO has been long linked to obesity. Studies have shown people with two copies of the “obese” version of the gene on average weigh nearly 7 lbs (3 kg) more and are about 70 percent more likely to be obese than those with other versions.
Gene Mutation Adds Risk in Child Kidney Transplants
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Screening for mutations in a gene that helps the body metabolize a kidney transplant anti-rejection drug may predict which children are at higher risk for side effects, including compromised white blood cell count or organ rejection, according to new research.
Published online Feb. 18 by the Nature journal Clinical Pharmacology and Therapeutics, the study suggests this genetic approach could also help physicians tailor personalized anti-rejection drug doses to prevent adverse reactions, said senior investigators Alexander A. Vinks, Pharm.D., Ph.D., and Jens Goebel M.D., of Cincinnati Children’s Hospital Medical Center.
“There are better ways than just giving standard doses of these drugs, and in due course these types of technologies will be available worldwide to help patients,” said Dr. Vinks, director of the Division of Clinical Pharmacology and the Pediatric Pharmacology Research Unit at Cincinnati Children’s. “This pilot study shows personalized and prospective MMF dosing and monitoring may be feasible to reduce the high incidence of drug toxicity in children without compromising the drug’s protective effects against kidney graft rejection.”
New CDC Study Assesses Impact of Genetic Testing on Health Outcomes
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Some genomic tests developed to personalize medical decisions about cancer care are beneficial, while for others the evidence is uncertain and reliance on the test might even lead to poorer medical management of cancer in some cases, according new recommendation statements from an expert panel. The statements appear in the January issue of Genetics in Medicine, the official peer-reviewed journal of The American College of Medical Genetics. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health, a leading provider of information and business intelligence for students, professionals, and institutions in medicine, nursing, allied health, pharmacy and the pharmaceutical industry.
Genetic tests for tumor gene expression in women with early-stage breast cancer to detect those at risk for cancer recurrence, the panel wrote, are based on insufficient evidence to determine whether they offer any improvement in health outcomes. The panel also found insufficient evidence to recommend testing for variants of the gene UGT1A1 in patients undergoing chemotherapy for metastatic colorectal cancer to inform use of the chemotherapy drug irinotecan. While the test might be useful in identifying patients at risk of side effects from the drug, reducing irinotecan dosage may be more harmful than the side effects, so the clinical utility of the UGT1A1 test is questionable, at best, it said.
On the other hand, genetic testing for Lynch syndrome, a hereditary condition that increases the risk of colorectal cancer, is useful to recommend screening relatives for the mutations that cause the syndrome and encouraging them to have regular colorectal cancer exams, the panel found.
Canada-US scientists discover gene responsible for brain’s aging
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Will scientists one day be able to slow the aging of the brain and prevent diseases such as Alzheimer’s and Parkinson’s? Absolutely – once the genetic coding associated with neuronal degeneration has been unraveled.
According to a new study published in The Journal of Neuroscience, a research team from the Université de Montréal, Maisonneuve-Rosemont Hospital and Lawrence Berkeley National Laboratory has taken a giant step in this direction by identifying a gene that controls the normal and pathological aging of neurons in the central nervous system: Bmi1.
The primary risk factor for diseases such as macular degeneration, Parkinson’s and Alzheimer’s is age. Although many researchers have sought to better understand the genetics and pathophysiology of these diseases, few studies have focused on the basic molecular mechanisms that control neuronal aging.
1 gene regulates pain, learning and memory
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In 2002, a group of scientists at the University of Toronto was able to identify a gene which they dubbed DREAM (downstream regulatory element antagonistic modulator). The gene’s function was highly interesting: it obviously served as a key regulator in the perception of pain. Mice who lacked the gene showed clear signs of markedly reduced sensitivity to all kinds of pain, whether chronic or acute. Otherwise, the mice appeared perfectly normal.
The work leading to these findings was carried out in the lab of Josef Penninger, then principal investigator at the Amgen Institute in Toronto. The publication describing the gene’s function was received with great interest (Cell, Vol. 108, 31-43, 11.1.2002) and DREAM was subsequently termed the “Master-Gene of pain perception”.
Josef Penninger, meanwhile scientific director of IMBA, the Institute of Molecular Biotechnology of the Austrian Academy of Sciences in Vienna, continued to wonder what other surprises DREAM might have in store. In a collaborative effort with neurobiologists from the University Pablo de Olivade (Seville) he devised experiments to follow up on the previous findings. A team of scientists under Ángel Manuel Carrión subjected DREAM-less mice to numerous neurological tests and analyzed their memory skills. The results were striking: without DREAM, mice were able to learn faster and remember better. Fascinatingly, the brains of aged mice (18 months) showed learning capacities similar to those of very young mice.
Chromosome disorder raises risk of death
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Turner syndrome, the most commonly diagnosed sex chromosome abnormality in women, not only leads to substantial illness but is also raises the risk of death, according to UK researchers.
“This study,” lead investigator Dr. Minouk J. Schoemaker told Reuters Health, “shows that mortality in women with Turner syndrome is three-fold higher than in the general population, and that mortality is raised for almost all major causes of death, and throughout adulthood.”
Turner syndrome is a genetic condition caused when one of the two X chromosomes that girls normally have is missing. It results in various physical characteristics and incomplete ovaries.
