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Genetic Linkage

Huntington’s Disease: 2 Steps Backward, 1 Step Forward

Last week's DNA Science post considered the ebb and flow of treatment possibilities for Alzheimer's disease. This week, it's Huntington's disease.

 

Like Alzheimer's, the less familiar HD also affects the brain, but HD is always inherited and is much rarer. The only treatments for HD manage symptoms, some of them prescribed off-label, borrowed from other conditions. A treatment that addresses the underlying cause of the disease, which delays onset or slows progression, has been elusive for decades.

 

A Disease Like No Other

 

HD is one of 40 "expanding repeat" diseases. A tiny part of a gene repeats many times, resulting in an encoded protein burdened with extra amino acids that interfere with its folding, rendering the protein sticky. In HD, mutant huntingtin protein gums up neurons in the brain's striatum, blocking signals essential to control movements and to think. Behavior changes too – anger and aggression may soar, as irritability, loss of impulse control, and confusion reign. The white matter part of the brain – the axons of those neurons – shrinks.

 

To continue reading, go to DNA Science, where this post first appeared.

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Alzheimer’s Treatments in the Pipeline and the False Promise of Prevagen: Distinguishing Hope from Hype

 
 
 

The avalanche of TV ads for Prevagen that coincided with my reaching Medicare age has inspired me to investigate what's coming for Alzheimer's disease (AD) – real treatments. Prevagen is not that.

 

Deceptive Advertising

 

The scenes, unending lest they immediately vanish from the viewer's disintegrating memory, show gorgeous older folks, especially couples, enjoying life and claiming that Prevagen keeps them thinking clearly, implying that they wouldn't have otherwise. A banner on the lower right proclaims "Prevagen improves memory." Yet there's no evidence that this is in fact true.

 

Prevagen pitches don't mention the class action lawsuit against Quincy Bioscience that was settled in 2020. Customers who had their receipt could get $70 back, and those who didn't, a generous $12. The red flag? Those claims to improve memory.

 

Prevagen, a "brain health supplement" and not a drug, falls into that regulatory backwater for products skirting rigorous clinical trials. The settlement demanded the company stop the claims, but "Buy Prevagen® Brain Health & Memory Improvement Supplements" appears instantly on Google. The asterisk above "Supplements" is the standard disclaimer: "These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease."

 

To continue reading, go to my DNA Science blog at Public Library of Science, where this post first appeared.

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Science Writing in the Age of COVID-19

It's been a strange and busy 15 months for science journalists.

 

Each day, throughout the day, our inboxes overflow with the latest from the technical medical and science journals – tables-of-contents, abstracts, news releases, and the never-ending stream of article preprints. We jumpstart the journals by going straight to medRxiv and bioRxiv, aka "med-archive" and "bio-archive," where investigators post articles before peer review.

 

Where We Get Information

 

It's a deluge, an unrelenting barrage of new reports from the Science and Nature family of journals; the medical journals like JAMA, the Lancet group, and the NEJM; and publications that cover more basic science, like Cell and the journals from Public Library of Science, which has sponsored this blog since 2012. The journals send wrap-ups on the weekends, in case we've missed anything.

 

The clearinghouse for news releases for journalists, Eurekalert, provides information from a wide range of publications, government agencies, academic institutions, research centers, nonprofits, and companies, with quotes from experts and images and videos we can use. Eurekalert added a COVID tab to the topics menu early in the pandemic. Much appreciated!

 

As we try to stay ahead of our inboxes, we're invited to webinars, zooms, and podcasts, all wonderfully helpful in crafting our stories.

 

To continue reading, go to my DNA Science blog at Public Library of Science, where this post first appeared.

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On the Anniversary of the Pandemic, Considering the Bioweapon Hypothesis

A year ago, the Director General of the World Health Organization, Tedros Adhanom Ghebreyesus, delivered the message that would divide time:

 

"WHO has been assessing this outbreak around the clock and we are deeply concerned both by the alarming levels of spread and severity, and by the alarming levels of inaction. We have therefore made the assessment that COVID-19 can be characterized as a pandemic."

 

What followed was a call to action to all. "We have rung the alarm bell loud and clear." And instantly, the redundant "global pandemic" ricocheted across the media, reverberating still.

 

The name of the enemy had changed quickly as 2020 began, from the "Wuhan coronavirus" to "2019 novel coronavirus" shortened to "2019-nCoV," and finally to SARS-CoV-2, acknowledging similarity to SARS, circa 2003-2004.

 

Whatever it's name, did SARS-CoV-2 have an older guise, perhaps in a lab?

 

The Bioweapon Hypothesis

 

To continue reading, go to DNA Science, where this post first appeared.

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Is COVID Optimism Finally Overtaking Pessimism? Harvard Experts Weigh In

Glimmers of hope are beginning to shine through the gloom of the past year. That was evident in a recent webinar that the Massachusetts Consortium on Pathogen Readiness (MassCPR) held to "demystify" the new viral variants. Each consists of several mutations.

 

Will the variants fuel "a novel stage of contagion, COVID 2.0?" opened George Daley, MD, PhD, dean of Harvard Medical School. "What has been unsettling is how many times mutations have cropped up independently in infected patients across the globe and in petri dishes. This is a consequence of Darwinian evolution by natural selection in real time," he added. The fact that the virus, SARS-CoV-2, has mutated in the same ways at different times and places suggests that the changes benefit the virus.

 

Also disturbing is that once variants appear, they proliferate. "That suggests the virus is more contagious, or replicates faster, so that it takes over the outbreak," said Jeremy Luban, MD, from the University of Massachusetts Medical School. Most mutations are neutral; we need to worry when they combine into "variants of concern," aka VOC. "They could permit the virus to escape immune control that's been established in a person from prior infection or from a vaccine," Luban added.

 

The "big three" variants of most concern now have hard-to-remember numerical names, which avoid stigmatizing a place: B.1.3.5.1 variant (South Africa), B.1.1.7 (UK), and P.1 (Brazil). The last one may be the worst to arise, so far. It first came to attention in Manaus, Amazonia. "Up to 70% of the population had been infected and they had developed what we'd consider herd immunity that would prevent new infection," Luban explained. The explosion of hospitalizations and deaths in December, a second wave, coincided with the appearance of the P.1 variant. "Many mutations in it raise concerns about whether the virus is resistant to the immune response against the first virus," he added.

 

Tackling variants requires asking three questions, Luban said:
• Do they enhance transmission?
• Do they permit reinfection?
• Do they decrease vaccine efficacy?

 

Fortunately, the vaccines so far are doing their job. Here are 6 pieces of good news.

 

To continue reading, go to DNA Science, where this post first appeared. 

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Rare Disease Day 2021: Gene Therapy Ups and Downs, Again

I can't believe it's been a decade since I researched and wrote The Forever Fix: Gene Therapy and the Boy Who Saved It. Since then I've shared stories of other families doing amazing things to help researchers develop treatments for their loved ones' rare diseases. The need is all the more compelling in these days of the pandemic.

 

Now entering its fourth decade, gene therapy continues along what seems at times a never-ending rocky road, riding the waves of fantastic success and plunging setbacks.

 

A Slow Start

 

The US has approved just two gene therapies. Luxturna has provided vision to patients with a form of retinal blindness (the basis of The Forever Fix), while Zolgemsa treats spinal muscular atrophy, a disease typically lethal in young children.

 

The latest in a series of setbacks, beginning in 1999 with the death of 18-year-old Jesse Gelsinger, came just yesterday. The FDA placed a clinical hold on two gene therapy trials for sickle cell disease, following reports of blood cancer in two trial participants. But that's not all.

 

To continue reading, go to DNA Science, where this post first appeared.

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Evoking Jeff Goldblum’s ‘The Fly’: Does growing human ‘brains-in-a-dish’ and creating chimeras cross a bioethical line?

Bits of human brain growing in a lab dish can reveal a great deal about how a disease begins and unfolds. But because the brain is also the seat of our consciousness and individuality, does disembodying it for science's sake pose bioethical challenges? 

 

That's what Stanford Law School researcher Henry (Hank) T. Greely addressed in "Human Brain Surrogates Research: The Onrushing Ethical Dilemma" in the January issue of The American Journal of Bioethics. Will the technology reach a stage at which the brain model is perhaps too close a mimic for comfort?

 

"If it looks like a human brain and acts like a human brain, at what point do we have to treat it like a human brain — or a human being?" he asks.

 

To continue reading, go to Genetic Literacy Project, where this post first appeared.

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DNA Study Adds Branch to North American Mammoth Family Tree

An international team has assembled billions of DNA snippets from molars that three mammoths left in the permafrost of northeastern Siberia, at widely different times. The research reveals an unrecognized ancestor that contributed half of the genome of the mammoth species that came to North America some 1.5 million years ago. The report appears in Nature.

 

The timescale of the study paints a portrait of mammoth evolution, perhaps even capturing a glimmer of speciation. The finding also sets back the clock of ancient DNA analysis; a horse that lived 780,000 to 560,000 years ago holds the record.

 

The three mammoth specimens were excavated in the 1970s from different locations in Siberia, dating from half a million to roughly 1.2 million years ago. They reside at the Geological Institute, Russian Academy of Sciences, in Moscow. The permafrost helped to preserve the DNA.

 

The Land Bridge Where It Happened

 

To continue reading, go to DNA Science, where this post first appeared.

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How My “Fruit Fly Love Story” Presaged The Rise of COVID-19 Viral Variants

I wrote "The Making of a Mutant" in 1978. Then a PhD student in the lab of Thom Kaufman at Indiana University, I snuck the story into a draft of a manuscript we were submitting to the journal Genetics – just to see if the boss was paying attention. The tale was about our research on the mutation Antennapedia in the fruit fly Drosophila melanogaster, which reroutes development so that legs grow where antennae normally extend.

 

My story was passed down to generations of graduate students, and read aloud at Thom's 60th birthday party many years later. I published "The Making of a Mutant" at Scientific American blogs in 2012, and then here at DNA Science in 2013. It's a geneticist's love story for Valentine's Day.

 

But never in a million years could I have imagined that my vision of a mutation that takes over a population would echo in the form of a novel coronavirus that is continually reinventing itself as it tears through human bodies and populations.

 

My story chronicles how the abnormal becomes the normal, and the new normal eventually spawns a new abnormal. That's what evolution is, change at the molecular level that reverberates up through populations of organisms – and viruses. The mutations in my imagined world in a milk bottle, home to the flies, were induced – in contrast to the situation for SARS-CoV-2.

 

We can't stop evolution. Mutation is a fundamental characteristic of a genetic material, endowing it with the plasticity that underlies adaptation, which fuels evolutionary change.

 

Evolution of SARS-CoV-2 in a Single Patient

 

 

To continue reading, go to DNA Science, where this post first appeared. 

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Getting a COVID Vaccine is More Transparent Than Eating a Hot Dog: Countering Vaccine Hesitancy

"So, you've been eatin' hot dogs and chicken nuggets all your life and you don't want the vaccine 'cuz you don't know what's in it??" asks a befuddled chicken in a meme.

 

Actually, plenty of information is out there about "what's in it."

 

Upon entering a vaccination center, you're handed a multi-page fact sheet that, among many other things, lists the chemicals about to be plunged into your arm.

 

The first two COVID vaccines are roughly the same recipe, adjusted for proportions and tiny details: mRNA, 4 fats (including cholesterol), a pinch of sugar, and a few salts. No eggs, preservatives, ricin, or leechee nut extract. (See The First COVID-19 Vaccines: What's mRNA Got to do With it?) Ingredient lists for hot dogs and chicken nuggets are far longer and complex.

 

Yet the comparative transparency of vaccine ingredient lists isn't enough to dispel the fear of something new and unfamiliar being jabbed into your body. For many people that fear arises against a backdrop of the history of dishonesty in medicine that has misled and mistreated marginalized groups, as well as the record of unethical clinical trials for some vaccines, notably influenza.

 

To continue reading go to my DNA Science blog at Public Library of Science, where this post first appeared.

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