Tag: genes

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Genetically Engineering Nature Will Be Way More Complicated Than We Thought

July 20, 2017

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For more than half a century, scientists have dreamed of harnessing an odd quirk of nature— “selfish genes,” which bypass the normal 50/50 laws of inheritance and force their way into offspring—to engineer entire species. A few years ago, the advent of the CRISPR-Cas9 gene editing technology turned this science fictional concept into a dazzling potential reality, called a gene drive. But after all the hype, and fear of the technology’s misuse, scientists are now questioning whether gene drives will work at all.

Gene drive is a molecular technology that forces an edited gene to be passed along into all of an organism’s offspring, overriding nature’s 50/50 inheritance mix. The first human-engineered gene drive was only demonstrated in fruit flies in 2015, but scientists were soon talking about using gene drives to exterminate invasive pests or kill off throngs of malarial mosquitoes.

But soon after, other researchers demonstrated that as an infertility mutation in female mosquitoes was successfully passed on to offspring over many generations, resistance emerged, allowing some mosquitoes to avoid inheriting the mutation. Just as bacteria can develop resistance to antibiotics, wild populations can develop resistance to modifications aimed at destroying them. Gene drive, dead.

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Image: By DBCLS 統合TV, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=55175302

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The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

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Revising the Ethical Framework for Deep Brain Stimulation for Treatment-Resistant Depression

By Somnath Das

Somnath Das recently graduated from Emory University where he majored in Neuroscience and Chemistry. He will be attending medical school at Thomas Jefferson University starting in the Fall of 2017. Studying Neuroethics has allowed him to combine his love for neuroscience, his interest in medicine, and his wish to help others into a multidisciplinary, rewarding practice of scholarship which to this day enriches how he views both developing neurotechnologies and the world around him. 

Despite the prevalence of therapeutics for treating depression, approximately 20% of patients fail to respond to multiple treatments such as antidepressants, cognitive-behavioral therapy, and electroconvulsive therapy (Fava, 2003). Zeroing on an effective treatment of “Treatment-Resistant Depression” (TRD) has been the focus of physicians and scientists. Dr. Helen Mayberg’s groundbreaking paper on Deep Brain Stimulation (DBS) demonstrates that electrical modulation an area of the brain called subgenual cingulate resulted in a “sustained remission of depression in four of six (TRD) patients” These patients experienced feelings that were described as “lifting a void,” or “a sudden calmness.” (Mayberg et al. 2005). The importance of this treatment lies in the fact participants who received DBS for TRD (DBS-TRD) often have no other treatment avenues, and thus Mayberg’s findings paved the way for DBS to have great treatment potential for severely disabling depression. 

Image courtesy of Wikimedia Commons
Because DBS involves the implantation of electrodes into the brain, Dr. Mayberg and other DBS researchers faced intense scrutiny following publication of their initial findings regarding the ethics of using what to some seems like a dramatic intervention for TRD.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

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The Uncertain Future of Genetic Testing

July 18, 2017

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AnneMarie Ciccarella, a fast-talking 57-year-old brunette with a more than a hint of a New York accent, thought she knew a lot about breast cancer. Her mother was diagnosed with the disease in 1987, and several other female relatives also developed it. When doctors found a suspicious lump in one of her breasts that turned out to be cancer, she immediately sought out testing to look for mutations in the two BRCA genes, which between them account for around 20 per cent of families with a strong history of breast cancer.

Ciccarella assumed her results would be positive. They weren’t. Instead, they identified only what’s known as a variant of unknown or uncertain significance (VUS) in both BRCA1 and BRCA2. Unlike pathogenic mutations that are known to cause disease or benign ones that don’t, these genetic variations just aren’t understood enough to know if they are involved or not.

“I thought you could have a mutated gene or not, and with all the cancer in my family, I believed I would carry a mutation. I didn’t know there was this huge third category,” she says. “I got no information – it felt like a huge waste of blood to get a giant question mark.”

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Image: © Catherine Losing

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The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

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Creative Minds: Reprogramming the Brain

Caption: Neuronal circuits in the mouse retina. Cone photoreceptors (red) enable color vision; bipolar neurons (magenta) relay information further along the circuit; and a subtype of bipolar neuron (green) helps process signals sensed by other photoreceptors in dim light.
Credit: Brian Liu and Melanie Samuel, Baylor College of Medicine, Houston.

When most people think of reprogramming something, they probably think of writing code for a computer or typing commands into their smartphone. Melanie Samuel thinks of brain circuits, the networks of interconnected neurons that allow different parts of the brain to work together in processing information.

Samuel, a researcher at Baylor College of Medicine, Houston, wants to learn to reprogram the connections, or synapses, of brain circuits that function less well in aging and disease and limit our memory and ability to learn. She has received a 2016 NIH Director’s New Innovator Award to decipher the molecular cues that encourage the repair of damaged synapses or enable neurons to form new connections with other neurons. Because extensive synapse loss is central to most degenerative brain diseases, Samuel’s reprogramming efforts could help point the way to preventing or correcting wiring defects before they advance to serious and potentially irreversible cognitive problems.

Melanie Samuel

Melanie Samuel

The human brain is wired with a vast number of circuits. They travel winding, contorted paths through the densely packed neurons in the human brain, making them extremely difficult to study. Samuel will start in less expansive and daunting neural terrain. She has chosen to focus first on synapses in the mouse retina, the complex neural tissue that lines the back of the eye.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

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Transferring Embryos with Genetic Anomalies

Jackie Leach Scully argues that respect for equality and diversity, and not just respect for the parental autonomy and the welfare of the future child, should inform policies governing the use of preimplantation genetic diagnosis.

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The Ethics Committee of the American Society for Reproductive Medicine recently published an Opinion on “Transferring embryos with genetic anomalies detected in preimplantation testing.” The Opinion aims to help providers deal with the rare but ethically difficult situation when prospective parents want to transfer embryos with a known genetic anomaly that is linked to a serious health-affecting disorder.

Preimplantation genetic diagnosis (PGD) is typically used by couples to avoid transferring a genetic anomaly to their children. Using PGD to ensure the transfer of a genetic anomaly, rather than avoid it, seems deeply counter-intuitive. Yet, there are several scenarios where this might happen. For example, this might be a reasonable option when the only transferable embryos carry the genetic anomaly, or when the embryos carry a different, but potentially just as serious, genetic variation.

The most problematic cases, however, occur when prospective parents express an actual preference for children with ‘their’ genetic condition – an anomalous condition that others perceive in negative terms. It’s an uncommon situation, but despite its rarity steps have been taken to block attempts by prospective parents to ‘choose disability’, such as the UK’s legislation on reproductive medicine. The legislation prohibits the use of an embryo (or gamete, in the case of egg and sperm donation) that has a genetic anomaly “involving a significant risk” of “a serious physical or mental disability, serious illness, or a serious medical condition” unless there are no other unaffected embryos or gametes that could be used instead.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

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Personalized Medicine: Our Future or Big Data Voodoo?

Kumar Ethirajan, MD

NOTE: Kumar Ethirajan, MD, an oncologist specializing in cancer genetics in the Kansas City area since 1993 and member of the Center for Practical Bioethics’ board of directors, will present this topic as part of the Center’s BIOETHICS MATTERS lecture series on Wednesday, July 19, 7:00 pm, at the Kansas City Public Library Plaza Branch, 4801 Main Street, Kansas City, MO. Bring your perspectives, questions and personal stories. Admission is free. All are welcome. 

Personalized medicine has the potential to revolutionize medicine. Actually, that’s not true. Personalized medicine IS REVOLUTIONIZING medicine. 

Personalized medicine IS our future! Yet, based on a 2013 survey by GfK, a global consumer research firm, just 27% of people have heard of the term personalized medicine and, of those, only 4% understand what the term means.

You may have heard personalized medicine referred to as genomic medicine, precision medicine or individualized medicine. Whatever you call it, it’s medicine that uses information about your genes to prevent, diagnose and treat disease. In cancer, it’s about using information about a tumor to discover certain biomarkers or genes and, hopefully, having a drug to treat it. So far, researchers have discovered more than 1800 disease genes, created more than 2,000 genetic tests for human conditions, and have 350 drugs currently in clinical trials.

So, this is great, right? Yes. But consider that some 30% of the world’s stored data is generated by the healthcare industry – and that a single patient on average generates 80 megabytes per year! With healthcare data exploding like this, shouldn’t we be thinking about the questions it raises?

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

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Huntington’s Disease: Gene Editing Shows Promise in Mouse Studies

My father was a folk song collector, and I grew up listening to the music of Woody Guthrie. On July 14th, folk music enthusiasts will be celebrating the 105th anniversary of Guthrie’s birth in his hometown of Okemah, OK. Besides being renowned for writing “This Land is Your Land” and other folk classics, Guthrie has another more tragic claim to fame: he provided the world with a glimpse at the devastation caused by a rare, inherited neurological disorder called Huntington’s disease.

When Guthrie died from complications of Huntington’s a half-century ago, the disease was untreatable. Sadly, it still is. But years of basic science advances, combined with the promise of innovative gene editing systems such as CRISPR/Cas9, are providing renewed hope that we will someday be able to treat or even cure Huntington’s disease, along with many other inherited disorders.

My own lab was part of a collaboration of seven groups that identified the Huntington’s disease gene back in 1993. Huntington’s disease occurs when a person inherits from one parent a mutant copy of the huntingtin (HTT) gene that contains extra repetitions, or a “stutter,” of three letters (CAG) in DNA’s four-letter code. This stutter leads to production of a misfolded protein that is toxic to the brain’s neurons, triggering a degenerative process that, over time, leads to mood swings, slurred speech, uncontrolled movements, and, eventually, death. In a new study involving a mouse model of Huntington’s disease, researchers were able to stop the production of the abnormal protein by using CRISPR tools to cut the stutter out of the mutant gene.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

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Responsibility in the age of precision genomics

by Alexa Woodward

Alexa is a fellow in the Precision Medicine: Ethics, Policy, and Culture project through Columbia University’s Center for the Study of Social Difference. The following is her reflection on the ongoing discussion around the Precision Medicine Initiative that has been the subject of recent political, social, and popular media attention. A recent presentation by Sandra Soo-Jin Lee, PhD, from the Center for Biomedical Ethics at Stanford University spurred our multi-disciplinary discussion of some of the following themes.

What is normal, anyway?

Genetically speaking, that’s precisely the question that the Obama administration’s Precision Medicine Initiative (PMI) seeks to answer. In recruiting and collecting comprehensive genetic, medical, behavioral, and lifestyle data from one million Americans, the scientific and medical communities will be better able to understand what constitutes normal genetic variation within the population, and in turn, what amount of variation causes or contributes to disease or disease risk.[1] Using this data, researchers could potentially create tailored approaches for intervention and treatment of an incredible range of diseases.

The PMI has a secondary aim: to increase the representation of previously underrepresented populations in research – primarily African Americans and Hispanics/Latinos. Inclusion of these groups in research has been a challenge for decades, with lack of access, distrust in the medical and research systems, and institutionalized racism all playing exclusionary roles. More broadly, outside of the government initiative, the promise of precision medicine ultimately seeks to alleviate disparities by finding and addressing supposed genetic differences, and empowering people with information to take responsibility for their health.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

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New Concerns Raised Over Value of Genome-Wide Disease Studies

June 21, 2017

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Compare the genomes of enough people with and without a disease, and genetic variants linked to the malady should pop out. So runs the philosophy behind genome-wide association studies (GWAS), which researchers have used for more than a decade to find genetic ties to diseases such as schizophrenia and rheumatoid arthritis. But a provocative analysis now calls the future of that strategy into question — and raises doubts about whether funders should pour more money into these experiments.

GWAS are fast expanding to encompass hundreds of thousands, even millions, of patients (see ‘The genome-wide tide’). But biologists are likely to find that larger studies turn up more and more genetic variants — or ‘hits’ — that have minuscule influences on disease, says Jonathan Pritchard, a geneticist at Stanford University in California. It seems likely, he argues, that common illnesses could be linked by GWAS to hundreds of thousands of DNA variants: potentially, to every single DNA region that happens to be active in a tissue involved in a disease.

In a paper published in Cell on 15 June1, Pritchard and two other geneticists suggest that many GWAS hits have no specific biological relevance to disease and wouldn’t serve as good drug targets. Rather, these ‘peripheral’ variants probably act through complex biochemical regulatory networks to influence the activity of a few ‘core’ genes that are more directly connected to an illness.

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Image via Flickr Attribution Some rights reserved by The Moonstone Archive

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The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

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Baby Genome Sequencing for Sale in China

June 15, 2017

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A Boston-based DNA sequencing company is offering to decode the complete genomes of newborns in China, leading some to ask how much parents should know about their children’s genes at birth.

Veritas Genetics says the test, ordered by a doctor, will report back on 950 serious early- and later-life disease risks, 200 genes connected to drug reactions, and more than 100 physical traits a child is likely to have.

Called myBabyGenome, the service costs $1,500 and could help identify serious hidden problems in newborns, the company says.

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MIT Technology Review

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The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.