Category Archives: Human Genetics

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Newswise It takes more mutations to trigger autism in women than in men, which may explain why men are four times more likely to have the disorder, according to a study published 26 February in the American Journal of Human Genetics1.

The study found that women with autism or developmental delay tend to have more large disruptions in their genomes than do men with the disorder. Inherited mutations are also more likely to be passed down from unaffected mothers than from fathers.

Together, the results suggest that women are resistant to mutations that contribute to autism.

This strongly argues that females are protected from autism and developmental delay and require more mutational load, or more mutational hits that are severe, in order to push them over the threshold, says lead researcher Evan Eichler, professor of genome sciences at the University of Washington in Seattle. Males on the other hand are kind of the canary in the mineshaft, so to speak, and they are much less robust.

The findings bolster those from previous studies, but don't explain what confers protection against autism in women. The fact that autism is difficult to diagnose in girls may mean that studies enroll only those girls who are severely affected and who may therefore have the most mutations, researchers note.

The authors are geneticists, and the genetics is terrific, says David Skuse, professor of behavioral and brain sciences at University College London, who was not involved in the study. But the questions about ascertainment are not addressed adequately.

Genetic burden:

The new study draws from the Simons Simplex Collection (SSC), a database of families that have one child with autism and unaffected parents and siblings. (This project is funded by the Simons Foundation, SFARI.orgs parent organization.) In a 2011 study, researchers found that girls with autism in the SSC tend to have more large duplications or deletions of regions of the genome, called copy number variants (CNVs), than do boys with the disorder, although this disparity does not reach statistical significance2.

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Girls Protected From Autism, Study Suggests

TIZIANA VAISITTI: LE RELAZIONI (MOLECOLARI) PERICOLOSE TRA CELLULE TUMORALI E MICROAMBIENTE..
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Researchers from the University of Sydney's Faculty of Health Sciences will build a human database to scientifically measure and classify what is 'normal' across the population.

The landmark 1000 Norms Project will catalogue human variation among healthy Australians between the ages of three to 100 to help clinicians better diagnose disease, direct treatment and evaluate patient progress.

Primary researchers for the project, Marnee McKay and Jennifer Baldwin, will measure the physical and health information of 1,000 healthy Australians, recording their body measurements and testing their balance, strength, power, coordination and movement. The study will also collect DNA saliva samples from participants to test for the ACTN3 gene, commonly referred to as the 'gene for speed', and evaluate the link between genetics and physical characteristics.

"This project will finally catalogue the normal physical variation in the Australian community and go some way towards helping answer the age-old question: am I normal?" said Ms McKay.

"While normal may be a loaded term, it's important for clinicians to be able to measure norms so they can assess health and function.

"In healthcare, knowledge of healthy human variation is essential for clinicians to make a diagnosis and to evaluate the effect of treatment."

Researcher Jennifer Baldwin said the database will be an invaluable tool for health policy makers providing a unique collection of healthy normative measures to better facilitate diagnosis and influence policy.

"The database will transform our understanding of the boundaries of health and disease and influence how we define healthy aging," Ms Baldwin said.

"Everyone accepts that no two human are the same, but to diagnose disease it is imperative we can reliably compare a patient's symptoms or physical limits against norms collected from the healthy population.

"As our population ages the study will allow clinicians and public policy makers to define healthy ageing and establish what is 'normal' during the ageing process.

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Researchers size-up what is 'normal'

PUBLIC RELEASE DATE:

20-Mar-2014

Contact: Dan Meyers dan.meyers@ucdenver.edu University of Colorado Denver

The same gene family that may have helped the human brain become larger and more complex than in any other animal also is linked to the severity of autism, according to new research from the University of Colorado Anschutz Medical Campus.

The gene family is made up of over 270 copies of a segment of DNA called DUF1220. DUF1220 codes for a protein domain a specific functionally important segment within a protein. The more copies of a specific DUF1220 subtype a person with autism has, the more severe the symptoms, according to a paper published in the PLoS Genetics.

This association of increasing copy number (dosage) of a gene-coding segment of DNA with increasing severity of autism is a first and suggests a focus for future research into the condition Autism Spectrum Disorder (ASD). ASD is a common behaviorally defined condition whose symptoms can vary widely that is why the word "spectrum" is part of the name. One federal study showed that ASD affects one in 88 children.

"Previously, we linked increasing DUF1220 dosage with the evolutionary expansion of the human brain," says James Sikela, PhD, a professor in the Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine. Sikela is the corresponding author of the study that was just published.

"One of the most well-established characteristics of autism is an abnormally rapid brain growth that occurs over the first few years of life. That feature fits very well with our previous work linking more copies of DUF1220 with increasing brain size. This suggests that more copies of DUF1220 may be helpful in certain situations but harmful in others."

The research team found that not only was DUF1220 linked to severity of autism overall, they found that as DUF1220 copy number increased, the severity of each of three main symptoms of the disorder -- social deficits, communicative impairments and repetitive behaviors became progressively worse.

In 2012, Sikela was the lead scientist of a multi-university team whose research established the link between DUF1220 and the rapid evolutionary expansion of the human brain. The work also implicated DUF1220 copy number in brain size both in normal populations as well as in microcephaly and macrocephaly (diseases involving brain size abnormalities).

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The gene family linked to brain evolution is implicated in severity of autism symptoms

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Newswise Many diseases have their origins in either the genome or in reversible chemical changes to DNA known as the epigenome. Now, results of a new study from Johns Hopkins scientists show a connection between these two maps. The findings, reported March 20 on the website of the American Journal of Human Genetics, could help disease trackers find patterns in those overlays that could offer clues to the causes of and possible treatments for complex genetic conditions, including many cancers and metabolic disorders.

By showing the connections between genetic variants and epigenetic information, we're providing epidemiologists with a road map, says Andrew Feinberg, M.D., M.P.H., a Gilman Scholar, the King Fahd Professor of Medicine and the director of the Center for Epigenetics in the Institute for Basic Biomedical Sciences at the Johns Hopkins University School of Medicine. Epigenetic tags show how disease-causing genetic variants might affect distant genes that in turn contribute to the disease.

Feinberg says it has long been known that individual genetic variants in sections of DNA that dont contain blueprints for proteins (once thought of as junk DNA) seem to alter the quantity of proteins produced far afield. That phenomenon has made it very hard for researchers to pinpoint the source of some genetic diseases or targets for their treatment. This study, Feinberg says, shows that these genetic variants may be acting on distant protein-forming genes by influencing epigenetic tags, or chemical add-ons, atop the DNA.

Feinberg; co-leader Dani Fallin, Ph.D., professor and chair of the Department of Mental Health at the Bloomberg School of Public Health and director of the Wendy Klag Center for Autism and Developmental Disabilities; and their team analyzed genetic data from hundreds of healthy participants in three studies to first figure out what a normal epigenetic pattern looks like. Although its now common to compare the genomes of healthy and sick populations to identify predispositions for diseases, it has not been possible to compare epigenomes this way. The researchers zoomed in on one type of epigenetic change, the attachment of a chemical tag called a methyl group to a particular site on DNA. Known as methylation, these tags affect whether genes produce any protein, and if so, how much.

The team then looked for the relationship between the resulting epigenetic data and genetic data. Human genetic code is marked by telltale blocks of DNA that children tend to inherit from their parents in unbroken chunks called haplotypes. One of these blocks is often fingered as a suspect when a genetic disease arises. However, since the blocks are comprised of hundreds of thousands of letters of DNA code, researchers are not often able to identify the culprit mutation, or the protein-forming genes it affects, which may lie somewhere else in the block.

Epigenetic signatures like methylation patterns also occur in blocks, which the team dubbed GeMes, for methylation blocks controlled by genes. The researchers found that the GeMes overlapped with the long genetic blocks but were much shorter.

That led them to suspect that the protein-coding genes turned on or off by those tags must be at the root of the disease associated with a particular genetic variant found elsewhere in the block.

Previously, people could not pinpoint the variants within a long stretch of DNA that were responsible for the disease, says Yun Liu, Ph.D., a postdoctoral fellow in Feinbergs laboratory. But now, by detecting just one variation in DNA methylation, or one GeMe, a researcher will know that one or more of the few hundred methylated nucleotides are possibly causing the disease.

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New Tool Pinpoints Genetic Sources Of Disease

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Dave King @ Cybersalon Human 2.0 - Technologies of Enhancement 27 February 2014 David King #39;s PhD in molecular biology is from Edinburgh University. He was th...

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Doctor Tom Borody claims faecal transplants curing incurable diseases like Crohn's

An Australian doctor claims he is curing incurable diseases using an all-natural waste product we usually flush away - human stool.

Professor Tom Borody has been championing the treatment, known as faecal microbiota transplantation (FMT), for 25 years.

As modern science begins to appreciate the critical role gut bacteria plays in human health, his treatment of diseases including Crohn's and colitis, auto immune diseases and even neurological disease is provoking both criticism and excitement.

While some doctors regard faecal transplants as potentially dangerous, two of Australia's biggest teaching hospitals are embarking on a large national trial.

Professor Borody is at science's new frontier, manipulating the bacteria that live in the human gut.

"In terms of genetics there are 3.1 million genes. That's a hell of a crowd of individuals living in our colon," he said.

Bacterial cells far outnumber human cells in our bodies and bacteria experts includingCSIRO's chief research scientist, Dr David Topping, believe the world is at the edge of an extraordinary medical revolution that will come through the understanding of the so-called human microbiome.

"I think we're on the edge of something extraordinary. The attention has switched entirely to the large bowel bacterial population which we now know is absolutely critical to human health," Dr Topping said.

Professor Borody is not waiting for controlled clinical trials to treat a range of diseases.

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Doctor Tom Borody claims faecal transplants curing incurable diseases like Crohn's

by Dhaneshi Yatawara

A cancer genetics clinic will be conducted by the Human Genetics Unit of the University of Colombo at the Maharagama National Cancer Institute. The clinic will be held every Friday afternoon.

The purpose of the clinic is to identify individuals having hereditary cancer syndromes and provide thorough evaluation, genetic counselling and testing which will be beneficial for the patients and their families, according to Professor Vajira Dissanayake of the Human Genetics Unit, Colombo University.

"We will work with physicians and surgeons who treat the patients. The clinic is ready to provide service not only to cancer patients but also to their family members as well," Prof. Dissanayake said.

The cancer genetics clinic will conduct risk assessments for each patient for all forms of cancers and screening for early detection management, Genetic counselling and genetic testing.

"Members of families with records of cancer occurring in multiple generations or people with two or more close relatives having the same cancer can come to the clinic and get their risk assessments," he said.

And for those who underwent treatment for cancer that occurred in one section of paired organs of the body have the facility to check whether the cancer has spread to the other half of the organ. Several main genetic tests will be available at the clinic.

Tests to check effectiveness of the drugs on individual cancer patients medically known as pharmacogenomic tests, are also available at the clinic.

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Genetics clinic at Cancer Institute

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Newswise Research from the University of Adelaide has confirmed that a gene linked to intellectual disability is critical to the earliest stages of the development of human brains.

Known as USP9X, the gene has been investigated by Adelaide researchers for more than a decade, but in recent years scientists have begun to understand its particular importance to brain development.

In a new paper published online in the American Journal of Human Genetics, an international research team led by the University of Adelaide's Robinson Research Institute explains how mutations in USP9X are associated with intellectual disability. These mutations, which can be inherited from one generation to the next, have been shown to cause disruptions to normal brain cell functioning.

Speaking during Brain Awareness Week, senior co-author Dr Lachlan Jolly from the University of Adelaide's Neurogenetics Research Program says the USP9X gene has shed new light on the mysteries of brain development and disability.

Dr Jolly says the base framework for the brain's complex network of cells begins to form at the embryo stage.

"Not surprisingly, disorders that cause changes to this network of cells, such as intellectual disabilities, epilepsy and autism, are hard to understand, and treat," Dr Jolly says.

"By looking at patients with severe learning and memory problems, we discovered a gene - called USP9X - that is involved in creating this base network of nerve cells. USP9X controls both the initial generation of the nerve cells from stem cells, and also their ability to connect with one another and form the proper networks," he says.

"This work is critical to understanding how the brain develops, and how it is altered in individuals with brain disorders.

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Critical Role of One Gene to Our Brain Development

Latest Diet & Weight Management News

WEDNESDAY, March 12, 2014 (HealthDay News) -- Scientists who identified a gene that appears to be strongly linked with obesity say their discovery could help efforts to find drug treatments for obesity and diabetes.

"Our data strongly suggest that [the gene] IRX3 controls body mass and regulates body composition," study senior author Marcelo Nobrega, an associate professor of human genetics at the University of Chicago, said in a university news release.

Although the research showed an association between the gene and obesity, it did not prove a cause-and-effect link.

The IRX3 gene was first pinpointed through an analysis of about 150 brain samples from people of European ancestry, according to the study, which was published online March 12 in the journal Nature.

To verify the role of IRX3 in obesity, the researchers created mice without the gene and found that they weighed about 30 percent less than normal mice. Much of this weight difference was due to reduced amounts of fat in the mice without the IRX3 gene.

"These mice are thin. They lose weight primarily through the loss of fat, but they are not runts," study co-author Chin-Chung Hui, a professor of molecular genetics at the University of Toronto, said in the news release.

"They are also completely resistant to high-fat diet-induced obesity," Hui said. "They have much better ability to handle glucose, and seem protected against diabetes."

The researchers also found that mice with altered function of the IRX3 gene in the hypothalamus -- the part of the brain that controls eating and energy output -- were as lean as mice that lacked the gene.

This suggests that the gene's activity in the hypothalamus controls body mass and composition in mice, and that genetic predisposition to obesity is wired in the brain, according to the study authors.

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Scientists Spot New Obesity Gene