Category Archives: Human Genetics

Human Genetics Lab Part 2 Vid
Pedigrees and inheritance of autosomal recessive traits.

By: Laura Anna See

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Human Genetics Lab Part 2 Vid - Video

Human Genetics Lab Part 3 Vid
Color-blindness.

By: Laura Anna See

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Human Genetics Lab Part 3 Vid - Video

BETHESDA, MD, USA and VIENNA, AUSTRIA - Two of the world's largest professional societies of human geneticists have issued a joint position statement on the promise and challenges of non-invasive prenatal testing (NIPT), a new procedure to test blood drawn from pregnant mothers for Down syndrome and other chromosomal disorders in the fetus. The document addresses the current scope of and likely future improvements in NIPT technology, ways it may best fit with existing prenatal screening tools and protocols, options and priorities in its implementation, and associated social and ethical issues.

The statement, drafted by the Social Issues Committee of the American Society of Human Genetics (ASHG) and the Public and Professional Policy Committee of the European Society of Human Genetics (ESHG), was published online March 18 in the European Journal of Human Genetics.

Current prenatal screening protocols for common structural abnormalities in the chromosomes vary among countries and medical practices. Generally, though, pregnant women are offered a combined first-trimester screening (cFTS), a risk assessment test based on blood and ultrasound markers. Women who receive abnormal cFTS results undergo a second step of testing to confirm or deny whether the fetus has an abnormality such as Down syndrome. This second step involves invasive procedures, such as amniocentesis, that in 0.5-1% of cases may lead to a miscarriage.

One important drawback of cFTS is the high rate of false alarms that lead to invasive procedures that put pregnancies at risk when the fetus is actually chromosomally normal. The main benefit of NIPT, apart from a significantly higher detection rate, is that it dramatically lowers the false alarm rate from about 5% to about 0.2%, making prenatal screening more accurate and safe. This is achieved by analyzing fragments of DNA in maternal blood, some of which provides information about the fetus. The fact that this 'fetal DNA' actually derives from the placenta is one reason why NIPT is not fully reliable. An important implication of this is that women who receive an abnormal NIPT result should still be advised to confirm this result through a second step of testing if they are considering a termination of pregnancy, the statement authors write.

The authors explored the benefits and drawbacks of various ways to implement NIPT, such as adding it to the current two-step process or using it to replace cFTS. As NIPT is significantly more expensive, the cost per test would need to be reduced considerably for the latter option to be feasible in fully funded prenatal screening programs, they noted. They also considered implications of the technology, including pressures on women to undergo the test and act upon the results, and the loss of ultrasound data that would indicate fetal problems if that step is removed from the screening process.

"Throughout our discussion, we kept in mind that the goal of prenatal screening is to enable autonomous, informed reproductive choices by pregnant women and their partners, not to prevent the birth of children with specific abnormalities," said Yvonne Bombard, PhD, 2014 chair of the ASHG Social Issues Committee.

The two committees also addressed emerging advances in NIPT technology that would allow testing for additional genetic conditions, such as rare microdeletion syndromes and syndromes that interfere with sexual development. They noted that as NIPT grows to include more conditions - producing results of varying certainty - pre-test genetic counseling will become significantly more complex.

"Although there is no convincing ethical reason to limit NIPT to Down syndrome and a few other chromosomal abnormalities, we are concerned about prematurely expanding NIPT to include rare conditions for which the test may not be sufficiently validated, or of which the clinical implications may not be fully understood. For example, parents-to-be will have to make difficult choices about how to act upon abnormal results for such conditions," said Wybo Dondorp, PhD, first author of the statement.

"A related concern about prematurely expanding the scope of the test is that it will reverse the significant decrease in false alarms and subsequent need for follow-up diagnostic procedures, which has been regarded as the main gain of NIPT in prenatal screening", said Diana Bianchi, MD, a member of the ASHG Social Issues Committee and co-author on the statement.

The statement authors also considered the longer-term question of how extensive prenatal genetic screening should be, and emphasized the role of infrastructure in enabling responsible use of NIPT. Priorities included educating health professionals and the public about its benefits and limitations, promoting equal access despite cost issues, controlling the quality of pre-test counseling and laboratory practices, and systematically evaluating the whole process. In all, the two committees published ten recommendations for the broader implementation of NIPT, including suggested next steps.

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ASHG and ESHG issue position statement on non-invasive prenatal screening

Two of the world's largest professional societies of human geneticists have issued a joint position statement on the promise and challenges of non-invasive prenatal testing (NIPT), a new procedure to test blood drawn from pregnant mothers for Down syndrome and other chromosomal disorders in the fetus. The document addresses the current scope of and likely future improvements in NIPT technology, ways it may best fit with existing prenatal screening tools and protocols, options and priorities in its implementation, and associated social and ethical issues.

The statement, drafted by the Social Issues Committee of the American Society of Human Genetics (ASHG) and the Public and Professional Policy Committee of the European Society of Human Genetics (ESHG), was published online March 18 in the European Journal of Human Genetics.

Current prenatal screening protocols for common structural abnormalities in the chromosomes vary among countries and medical practices. Generally, though, pregnant women are offered a combined first-trimester screening (cFTS), a risk assessment test based on blood and ultrasound markers. Women who receive abnormal cFTS results undergo a second step of testing to confirm or deny whether the fetus has an abnormality such as Down syndrome. This second step involves invasive procedures, such as amniocentesis, that in 0.5-1% of cases may lead to a miscarriage.

One important drawback of cFTS is the high rate of false alarms that lead to invasive procedures that put pregnancies at risk when the fetus is actually chromosomally normal. The main benefit of NIPT, apart from a significantly higher detection rate, is that it dramatically lowers the false alarm rate from about 5% to about 0.2%, making prenatal screening more accurate and safe. This is achieved by analyzing fragments of DNA in maternal blood, some of which provides information about the fetus. The fact that this 'fetal DNA' actually derives from the placenta is one reason why NIPT is not fully reliable. An important implication of this is that women who receive an abnormal NIPT result should still be advised to confirm this result through a second step of testing if they are considering a termination of pregnancy, the statement authors write.

The authors explored the benefits and drawbacks of various ways to implement NIPT, such as adding it to the current two-step process or using it to replace cFTS. As NIPT is significantly more expensive, the cost per test would need to be reduced considerably for the latter option to be feasible in fully funded prenatal screening programs, they noted. They also considered implications of the technology, including pressures on women to undergo the test and act upon the results, and the loss of ultrasound data that would indicate fetal problems if that step is removed from the screening process.

"Throughout our discussion, we kept in mind that the goal of prenatal screening is to enable autonomous, informed reproductive choices by pregnant women and their partners, not to prevent the birth of children with specific abnormalities," said Yvonne Bombard, PhD, 2014 chair of the ASHG Social Issues Committee.

The two committees also addressed emerging advances in NIPT technology that would allow testing for additional genetic conditions, such as rare microdeletion syndromes and syndromes that interfere with sexual development. They noted that as NIPT grows to include more conditions -- producing results of varying certainty -- pre-test genetic counseling will become significantly more complex.

"Although there is no convincing ethical reason to limit NIPT to Down syndrome and a few other chromosomal abnormalities, we are concerned about prematurely expanding NIPT to include rare conditions for which the test may not be sufficiently validated, or of which the clinical implications may not be fully understood. For example, parents-to-be will have to make difficult choices about how to act upon abnormal results for such conditions," said Wybo Dondorp, PhD, first author of the statement.

"A related concern about prematurely expanding the scope of the test is that it will reverse the significant decrease in false alarms and subsequent need for follow-up diagnostic procedures, which has been regarded as the main gain of NIPT in prenatal screening," said Diana Bianchi, MD, a member of the ASHG Social Issues Committee and co-author on the statement.

The statement authors also considered the longer-term question of how extensive prenatal genetic screening should be, and emphasized the role of infrastructure in enabling responsible use of NIPT. Priorities included educating health professionals and the public about its benefits and limitations, promoting equal access despite cost issues, controlling the quality of pre-test counseling and laboratory practices, and systematically evaluating the whole process. In all, the two committees published ten recommendations for the broader implementation of NIPT, including suggested next steps.

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Position statement on non-invasive prenatal screening issued

The discovery could help scientists develop more effective drugs to combat alcoholism

Virginia Commonwealth University School of Medicine researchers have discovered a biological clue that could help explain why some drinkers develop a dependence on alcohol and others do not.

The findings move researchers closer to identifying those at risk for addiction early and designing better drug treatments to help people stop drinking.

About 18 million people in the United States have an alcohol use disorder, according to National Institutes of Health statistics. The vast majority go untreated.

"There are few and inadequate pharmacological treatments to help people who want to stop drinking, because this is a terrifically difficult human genetics problem," said Jill C. Bettinger, Ph.D., associate professor in the Department of Pharmacology and Toxicology, VCU School of Medicine. "If we can better understand the molecular effects of alcohol, we can design more rational treatments and even warn people who are more susceptible to developing a dependence."

Bettinger is the senior author of a paper, "SWI/SNF Chromatin Remodeling Regulates Alcohol Response Behaviors in Caenorhabditis Elegans and is Associated With Alcohol Dependence in Humans," published Feb. 23 in the journal Proceedings of the National Academy of Sciences.

The paper describes how researchers examined the role of a protein complex -- called switching defective/sucrose nonfermenting (SWI/SNF) -- in determining the behavioral response of roundworms to alcohol.

Researchers watched through microscopes as the tiny worms became drunk on ethanol, studying how their initial sensitivity to the alcohol and tolerance changed based on which genes were expressed within the SWI/SNF complex.

Because humans and worms have a similar genetic makeup, Bettinger then turned to Brien P. Riley, Ph.D., associate professor in the Departments of Psychiatry and Human and Molecular Genetics at VCU School of Medicine and co-author of the recently published paper. Riley is director of the Molecular Genetics Lab at the Virginia Institute for Psychiatric and Behavioral Genetics, where researchers have been studying the human genome and its relationship to the risk of illness or other traits.

Riley found that naturally occurring genetic variations in the same SWI/SNF complex so crucial to a worm's tolerance were also associated with alcohol dependence in humans. Unlike Huntington's and other diseases, which can be linked to a mutation in a single gene, the evidence suggests that the likelihood to develop alcoholism is the product of mutations in many genes, each with small effect. The SWI/SNF complex genes represent a piece of that puzzle.

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Researchers find link between genetic variation and alcohol dependence

Anne O'Donnell Luria, M.D., Ph.D., Boston Children's Hospital; Mari Mori, M.D., Duke University; Laurie Robak M.D., Ph.D., Baylor College of Medicine receive Pfizer/ACMG Foundation Clinical Genetics Combined Residency for Translational Genomic Scholars Aw

Anne O'Donnell Luria, MD, PhD, of Boston Children's Hospital, Mari Mori, MD of Duke University, and Laurie Robak MD, PhD of Baylor College of Medicine were honored as the 2015-2016 recipients of the Pfizer/ACMG Foundation Clinical Genetics Combined Residency for Translational Genomic Scholars Fellowship Award at the ACMG 2015 Annual Clinical Genetics Meeting in Salt Lake City, Utah.

The objective of this fellowship is to provide an in-depth clinical research training experience at a premier medical center with expertise and significant clinical volume in the area of biochemical genetics, including lysosomal storage diseases, as well as in therapeutics and clinical trials involving patients with these and other metabolic diseases and, thereby, to increase the number of medical geneticists with interest, knowledge, and expertise in this area.

This Award grants $75,000 per year to the three recipients selected by the ACMG Foundation through a competitive process and will provide for the sponsorship of one year of the trainee's clinical genetics subspecialty in translational genomics following residency.

Dr. O'Donnell Luria received her MD and PhD at Columbia University, New York, and is currently completing a combined residency in Pediatrics and Medical Genetics at Boston Children's Hospital, Boston MA. "I am honored to receive the Pfizer/ACMG Foundation Translational Genomics Scholars Fellowship Award. I appreciate the support from Pfizer and the ACMG Foundation to gain additional training in biochemical genetics. I am grateful for the excellent training environment provided by wonderful clinicians, staff, and families that I have had the pleasure to work and train with at Harvard Medical School, Boston Children's Hospital, and Massachusetts General Hospital. This fellowship supports my efforts to begin a research program looking at transcriptional and epigenetic variation in lysosomal storage disease, with an aim of identifying new biomarkers of disease and potential therapeutic targets." Her research during the award period will focus on diagnosis and management of infants, children and adults with inborn errors of metabolism and the impact of epigenetic alterations.

Dr. Mori received her MD at Nagasaki University School of Medicine, Nagasaki, Japan, and MS in Biomedical Informatics at University of Pittsburgh, Pittsburgh PA. She is currently completing her Medical Biochemical Genetics Fellowship at Duke University Medical Center, Durham, NC, after completing a General Genetics Residency at Nationwide Children's Hospital/Ohio State University in Columbus, OH. Her research during the award period will focus on the identification of modifier genes from carefully phenotyped patients with Pompe disease at Duke University Medical Center. "I am deeply honored to be one of the recipients of the Pfizer/ACMG Foundation award. The award allows me to extend my biochemical genetics training to investigate factors that affect variable phenotypes of Pompe disease, under the guidance of Dr. Priya Kishnani, Professor of Pediatrics Division Chief, Medical Genetics at Duke University. The research would lead to a better understanding of prognostication of rare Mendelian diseases, and would have clinical impacts, especially for asymptomatic patients with a lysosomal disease detected by newborn screening."

Dr. Robak received her MD and PhD at University of Rochester, Rochester NY, and is currently completing her combined residency in Pediatrics and Medical Genetics at Baylor College of Medicine. Her research during the award period will focus on exploring the links between Lysosomal Storage Disorders and Parkinson 's disease at Baylor College of Medicine. "I am honored to be a recipient of the 2015 Pfizer/ACMG Foundation Fellowship Award. This June, I will be completing my combined Pediatrics/Medical Genetics residency at Baylor College of Medicine. This prestigious award will allow me to continue my research investigating potential links between lysosomal storage disorders and adult-onset neurodegenerative disorders. My project will be under the guidance of Dr. Joshua Shulman, Assistant Professor of Neurology and Molecular & Human Genetics at Baylor College of Medicine. By providing critical support during my transition from residency to junior faculty, this fellowship will promote my successful career development as a physician-scientist."

"With all of the advances in genomics, the Pfizer/ACMG Foundation Clinical Genetics Combined Residency for Translational Genomic Scholars presents an important opportunity to develop new approaches to diagnosis and treatment of genetic disorders. This fellowship is therefore a key component of our initiative to train physician scientists to be leaders in translational research in medical genomics," said Bruce R. Korf, MD, PhD, FACMG, president of the ACMG Foundation.

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Note to editors: To arrange interviews with experts in medical genetics, contact Kathy Beal, MBA, ACMG Director of Public Relations at kbeal@acmg.net or 301-238-4582.

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Dr. Luria, Mori and Robak receive Pfizer/ACMG Foundation Translational Genomic Fellowship Award

chemagic 360 - High Quality DNA/RNA Isolation
Based on PerkinElmer patented magnetic bead technology the chemagic 360 represents the ideal solution for nucleic acid isolation in a variety of research marketing segments, including but not...

By: PerkinElmer, Inc.

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chemagic 360 - High Quality DNA/RNA Isolation - Video

Si celebra oggi la decima Giornata mondiale della sindrome di Down. Una data, il 21 marzo, che non stata scelta a caso visto che la sindrome nota anche come Trisomia 21. A scoprirla e a darle questo nome fu il genetista, pediatra e attivista francese Jrme Lejeune (19261994), proclamato servo di Dio dalla Chiesa cattolica. I suoi "21 Pensieri", che vi riproponiamo di seguito in inglese, con la promessa di tradurli presto, sono una manifesto in difesa della vita e della persona umana.

1. Human genetics can be summarized in this basic creed: In the beginning is the message, and the message is in life, and the message is life. And if the message is a human message, then the life is a human life.

2. Life has a very long history, but each of us has a very definite beginningthe moment of conception.

3. A month after conception, a human being is one-sixth of an inch long. The tiny heart has already been beating for a week, and the arms, legs, head and brain have already begun to take shape. At two months, the child would fit into a walnut shell: Curled up, she measures a little more than an inch long. Inside your closed fist, she would be invisible, and you could crush her without meaning toeven without noticing. But if you open your hand, she is virtually complete, with hands, feet, head, internal organs, brain, everything in place. All she needs to do is grow. Look even more closely with a standard microscope, and you'll be able to make out her fingerprints. Everything needed to establish her identity is already in place.

4. Hate the disease, love the patient: That is the practice of medicine.

5. Again and again we see this absolute misconception of trying to defeat a disease by eliminating the patient! It's ridiculous to stand beside a patient and solemnly say, Who is this upstart who refuses to be cured? How dare he resist our art? Let's get rid of him! Medicine becomes mad science when it attacks the patient instead of fighting the disease. We must always be on the patient's side, always.

6. When parents are worried about a sick child, we have no right to make them waitnot even one nightif we can do otherwise.

7. Either we will cure them of their innocence, or there will be a new massacre of the innocents.

8. I see only one way left to save them, and that is to cure them. The task is immensebut so is Hope.

9. We will beat this disease. It's inconceivable that we won't. It will take much less intellectual effort than sending a man to the Moon.

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Quei "21 Pensieri" sulla Giornata per i Down

For decades, evolutionists have believed that when it comes to human reproduction, it's a case of survival of the fittest. However a new study into human genetics actually shows that wealth and power play an even stronger role.

AUT Professor Steve Pointing says in the last few thousand years, brawn's role in deciding which men pass down their genes is becoming less important.

"If a particular organism has favourable traits for environment, it will pass on more of its genes and have more offspring than if you have less favourable traits," he explained on Firstline this morning.

"But there's growing evidence now that in humans, the reverse is true we're actually dictating evolution because the wealth and power aspect of our society is actually driving evolution of our species."

The research, conducted by Arizona State University, looked at the Y chromosome of 500 men worldwide. They found that between 4000 and 8000 years ago, there was a bottleneck in genetic diversity for males.

At the same time, female genetic diversity was increasing rapidly implying at the time, only a few men were mating with many women.

"The smoking gun for that is the change from a nomadic, hunter-gatherer society to a more agrarian society, where we know wealth and power become concentrated in fewer individuals."

The findings are concerning for the future of the human race, because any loss in genetic diversity is "bad news".

"It means that as a species we become more susceptible to catastrophic diseases and events," says Prof Pointing.

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Study: Wealth and power key to men's genetic success

Britain may be famous for preserving its royal DNA, but a genetic analysis of the nation is providing new insights into the "story of the masses," according to scientists.

Researchers announced Wednesday that they had created the world's first fine-scale genetic map of any country, an achievement that allowed them to settle a few long-running debates about the history and bloodlines of England, Scotland, Wales and Northern Ireland.

The group's most surprising finding was its failure to identify a single "Celtic" genetic group. In fact, the researchers said that the Celtic regions of Scotland, Northern Ireland, Wales and Cornwall were among the most genetically different.

Likewise, they found no clear genetic evidence of the Danish Viking occupation and control of a large part of England during the 9th century, suggesting a "relatively limited input of DNA."

The research, which was published Wednesday in the journal Nature, was conducted by an international team and led by scientists from the University of Oxford, University College London and the Murdoch Children's Research Institute in Australia.

ThePeople of the British Isles study was based on sophisticated statistical analysis of DNA samples from 2,030 rural British residents. Each of the whiteDNA donors had all four of their grandparents born within 48 miles of one another, essentially allowingresearchers to sample the DNA of the grandparents in specific regions.

The DNA samples were studied for differences at roughly half a million positions along the genome, and were then grouped by similarity. Researchers plotted each DNA donor on a map, positioning the donorsat the geographic midpoint of their grandparents' birthplaces.

"What was striking was the pattern of variation we saw and the way it aligned with geography," said coauthor Peter Donnelly, director of the Wellcome Trust Center for Human Genetics at the University of Oxford.

Subtle yet identifiable genetic patterns could be found separated by current-day county lines, Donnelly said. Such was the case with Cornwall and Devon, in England's southwest.

In order to provide context, researchers alsoanalyzed DNA samples from 6,209 volunteers from 10 other European nations. That data allowed researchers to determine the genetic contributions of people from other parts of Europe.

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Study of Britain produces first fine-scale genetic map of a nation