Search

Got no COVID-19 symptoms? A gene mutation might be the reason

<div> <div class="copy"> A global study has unearthed a possible genetic reason why some people infected with the virus that causes COVID-19 show no symptoms. Human leukocyte antigens – or HLAs – are important genes that support immune function in the human body, particularly in identifying viral pathogens. And a particular variation in the HLA-B complex has been found to at least double the likelihood that a person infected with SARS-CoV-2 will be asymptomatic. For people who inherit a copy of the HLA-B15 variant from one parent, there was a 2.4 times greater chance of avoiding symptoms. Homozygous carriers — born with copies of the variant from each parent — were 8.5 times more likely to avoid symptoms. It’s a somewhat common variant among certain ethnicities – about 1 in 10 people with European ancestry are potential carriers – but having the gene is not a guaranteed protector against coronavirus symptoms. The findings, <a href="https://doi.org/10.1038/s41586-023-06331-x" target="_blank" rel="noreferrer noopener" data-type="URL" data-id="https://doi.org/10.1038/s41586-023-06331-x">published</a> in Nature, have emerged from a joint study between researchers at the University of California San Fransisco and Australian institutions including Latrobe University, Monash University and the QIMR Berghofer Centre. The research came about almost by accident. <div class="in-content-area content-third content-right"><a href="https://cosmosmagazine.com/health/covid/link-between-blood-type-and-risk-of-covid-19-infection/"> </a></div> Co-lead authors Professor Stephanie Gras from Latrobe and Jill Hollenbach from UCSF first met at a research conference in May 2022 and pooled their resources to track the association of possible gene variations with COVID-19 symptoms. Their teams narrowed a group of 30,000 people with high-quality HLA data to a cohort of about 1,500 unvaccinated people who tested positive for the virus. They then focussed on five locations of interest in the HLA genes while monitoring the emergence of symptoms to determine which variants, if any, might have a greater linkage to being COVID asymptomatic. “The [SARS-CoV-2] virus gets inside cells and ‘presents’ some small part of the virus on the surface via the HLA molecule,” Gras explains. “Those act as a red flag for T cells. The cell sends the signal to the T cell that it has been infected with the virus, and the T cells get activated and kill that [infected] cell. “HLA-B15 can actually present a small part of the spike protein that is very similar between SARS-CoV-2 and seasonal coronaviruses… [that] circulate every year in the population and give us the common cold during winter most of the time. They share some similarities.” The understanding provides a possible application for future treatments. Now an association between the variant and asymptomatic cases has been identified, the Gras and Hollenbach teams have begun to study the interaction between HLA-B15 and the SARS-CoV-2 spike protein at the atomic level. That research is already underway, including at the Australian Synchrotron at the Australian Nuclear Science and Technology Organisation. “We’re doing atomic-level models of proteins to understand the interaction,” Gras says. “We want to compare the T cells within people who are asymptomatic with HLA-B15 and people who are not asymptomatic with HLA-B15. Actually, HLA-B15 is not a magic bullet, you can have it and still have severe COVID.” Image credits: Getty Images </div> <div id="contributors"> <a href="https://cosmosmagazine.com/health/covid/got-no-covid-19-symptoms-a-gene-mutation-might-be-the-reason/">This article</a> was originally published on <a href="https://cosmosmagazine.com">Cosmos Magazine</a> and was written by <a href="https://cosmosmagazine.com/contributor/matthew-agius">Matthew Ward Agius</a>. </div> </div>

Body

Genetic mutations slowly accumulated over a lifetime change blood production after 70 years of age

Ageing is likely caused by the gradual accumulation of molecular damage, or genetic mutations, in the cells of our bodies that occurs over a lifetime. But how this translates into the rapid deterioration in organ function that’s seen after the age of 70 has so far not been clear. Now, scientists have discovered that the accumulation of genetic mutations in blood stem cells are likely responsible for the abrupt change in how <a class="spai-bg-prepared" href="https://cosmosmagazine.com/science/biology/why-do-we-have-blood/" target="_blank" rel="noreferrer noopener">blood</a> is produced in the body after 70 years of age. The <a class="spai-bg-prepared" href="https://www.nature.com/articles/s41586-022-04786-y" target="_blank" rel="noreferrer noopener">new study</a>, published in Nature, points to a change in the diversity of stem cells that produce blood cells as the reason why the prevalence of reduced cell regeneration capacity, <a class="spai-bg-prepared" href="https://www.frontiersin.org/articles/10.3389/fonc.2020.579075/full" target="_blank" rel="noreferrer noopener">cytopenia</a> (one or more blood cell types is lower than it should be), immune disfunction, and risk of blood cancer dramatically rises after 70. “We’ve shown, for the first time, how steadily accumulating mutations throughout life lead to a catastrophic and inevitable change in blood cell populations after the age of 70,” says joint-senior author Dr Peter Campbell, head of the Cancer, Ageing and Somatic Mutation Program at the Wellcome Sanger Institute, UK. “What is super exciting about this model is that it may well apply in other organ systems too.” Blood cells are made in a process called haematopoiesis All of the cells in our blood – including red cells, white cells and platelets – develop in a process called haematopoiesis from haematopoietic stem cells in our bone marrow. These stem cells are what’s known as multipotent progenitor cells, which simply means that they can develop into more than one cell type. Researchers were interested in better understanding how this process changes as we age, so they sequenced the entire genomes of 3,579 haematopoietic stem cells from a total of 10 people – ranging in age from newborn to 81 years. <div class="newsletter-box spai-bg-prepared"> <div id="wpcf7-f6-p193434-o1" class="wpcf7 spai-bg-prepared" dir="ltr" lang="en-US" role="form"> <form class="wpcf7-form mailchimp-ext-0.5.61 spai-bg-prepared init" action="/science/mutations-change-blood-production/#wpcf7-f6-p193434-o1" method="post" novalidate="novalidate" data-status="init"> <input class="wpcf7-form-control wpcf7-text referer-page spai-bg-prepared" name="referer-page" type="hidden" value="https://www.google.com/" data-value="https://www.google.com/" aria-invalid="false" /> </form> </div> </div> Using this information, they were able to construct something similar to a family tree (<a class="spai-bg-prepared" href="https://www.nature.com/scitable/topicpage/reading-a-phylogenetic-tree-the-meaning-of-41956/#:~:text=A%20phylogenetic%20tree%2C%20also%20known,genes%20from%20a%20common%20ancestor." target="_blank" rel="noreferrer noopener">a phylogenetic tree</a>) for each stem cell, showing how the relationships between blood cells changes over the human lifespan. They found that in adults under 65, blood cells were produced from between 20,000 and 200,000 different stem cells – each contributing roughly equal amounts to production. But after 70 years of age they observed a dramatic decrease in the diversity of stem cells responsible for haematopoiesis in the bone marrow. In fact, only 12-18 independent expanded sets of stem cell clones accounted for 30-60% of cell production. These highly active stem cells had outcompeted others and progressively expanded in numbers (clones) across that person’s life, and this expansion (called <a class="spai-bg-prepared" href="https://www.nature.com/articles/s41586-022-04785-z" target="_blank" rel="noreferrer noopener">clonal haematopoiesis</a>) was caused by a rare subset of mutations known as driver mutations that had occurred decades earlier. “Our findings show that the diversity of blood stem cells is lost in older age due to positive selection of faster-growing clones with driver mutations. These clones ‘outcompete’ the slower growing ones,” explains lead researcher Dr Emily Mitchell, a haematology registrar at Addenbrooke’s Hospital,UK, and PhD student at the Wellcome Sanger Institute, US. “In many cases this increased fitness at the stem cell level likely comes at a cost – their ability to produce functional mature blood cells is impaired, so explaining the observed age-related loss of function in the blood system.” Which clones became the dominant stem cells varied between individuals, which explains why variation is seen in disease risk and other characteristics in older adults. “Factors such as chronic inflammation, smoking, infection and chemotherapy cause earlier growth of clones with cancer-driving mutations. We predict that these factors also bring forward the decline in blood stem cell diversity associated with ageing,” says joint-senior author Dr Elisa Laurenti, assistant professor at the Wellcome-MRC Cambridge Stem Cell Institute, UK. “It is possible that there are factors that might slow this process down, too,” she adds. “We now have the exciting task of figuring out how these newly discovered mutations affect blood function in the elderly, so we can learn how to minimise disease risk and promote healthy ageing.”  <img id="cosmos-post-tracker" class="spai-bg-prepared" style="opacity: 0; height: 1px!important; width: 1px!important; border: 0!important; position: absolute!important; z-index: -1!important;" src="https://syndication.cosmosmagazine.com/?id=193434&title=Genetic+mutations+slowly+accumulated+over+a+lifetime+change+blood+production+after+70+years+of+age" width="1" height="1" />  <div id="contributors"> <a href="https://cosmosmagazine.com/science/mutations-change-blood-production/" target="_blank" rel="noopener">This article</a> was originally published on <a href="https://cosmosmagazine.com" target="_blank" rel="noopener">Cosmos Magazine</a> and was written by <a href="https://cosmosmagazine.com/contributor/imma-perfetto" target="_blank" rel="noopener">Imma Perfetto</a>. Imma Perfetto is a science writer at Cosmos. She has a Bachelor of Science with Honours in Science Communication from the University of Adelaide. Image: Getty Images </div>

Body

A genetic mutation makes some people need less sleep

Though most of us feel the consequences of missing out on a full night’s sleep, a lucky few don’t - thanks to a rare genetic mutation. According to a study published in <a rel="noopener" href="https://www.cell.com/neuron/fulltext/S0896-6273(19)30652-X" target="_blank">Neuron</a>, some people who can function normally on six hours of sleep carry an altered version of a particular gene, making it the second to be associated with short sleep. In their previous research in <a rel="noopener" href="https://science.sciencemag.org/content/325/5942/866" target="_blank">2009</a>, the team found a mother and daughter - who felt rested after about six hours of sleep at night - both had a mutation in a gene called DEC2. The DEC2 gene codes for a protein that stops other genes from expressing. One of these genes that the protein inhibits controls a hormone called orexin, which is known to regulate wakefulness. In the follow-up study, the scientists studied another family of naturally short sleepers and have identified another mutation, which they estimate about four in every 100,000 people have. The scientists engineered mice to have the same mutation and found that they slept, on average, one hour less per day than control mice without the mutation. For the family of humans with the mutation, they slept an average of two hours less per day than those without the mutation. The mutated gene, called ADRB1, encodes a receptor for a neural signalling molecule called noradrenaline. In mouse brains, the cells that had this receptor were active while they were awake and quiet during deep sleep, according to the researchers. They propose that the mutation makes these neurons more active, which could explain why its human carriers sleep for shorter periods of time. Though this research has been conducted on small groups, it could pave the way for the development of drugs that target these kinds of mutations or help those with sleeping disorders feel better while getting little sleep.

Body

New fears as COVID-19 UK variant mutates again

<div class="post_body_wrapper"> <div class="post_body"> <div class="body_text redactor-styles redactor-in"> Scientists have warned that the highly contagious UK variant of COVID-19 has mutated again and may give the virus the ability to evade the immune system. Public Health England reported that some sample tests detected genomes with the E484K mutation, which has been seen in the highly contagious South African and Brazilian variants of COVID-19. Calum Semple told BBC radio that this mutation is of "most concern" and seems to have developed spontaneously in the UK varient. “The mutation of most concern, which we call E484K, has also occurred spontaneously in the new Kent strain in parts of the country too,” said Professor Semple, a member of the Scientific Advisory Group for Emergencies (SAGE). UK Health Secretary Matt Hancock said that a further 11 cases of mutations of concern had been identified in Bristol and 32 in Liverpool. Authorities in parts of London, the West Midlands, East, South East and North West England have started offering door-to-door and mobile COVID-19 testing in a push to test 80,000 people for the mutation. “In all these areas it is imperative that people must stay at home and only leave home where it is absolutely essential,” Hancock said. Testing is being offered to everyone in these areas over the age of 16, even if they have had the vaccine. “The message is more important than ever to stay at home, maintain social distancing and get tested," Hancock explained. “We must all keep at it, we’ve sacrificed so much,” he added, warning of “difficult weeks ahead”. </div> </div> </div>

News

New coronavirus mutations on the rise

The race against the virus that causes COVID-19 has taken a new turn: Mutations are rapidly appearing, and the longer we wait for a vaccine, the more likely it is that a variant can surpass current tests and treatments. Coronavirus is quickly becoming more genetically diverse, and health officials say the high rate of cases is the main reason. Each new infection gives the virus a chance to mutate as it duplicates itself, threatening to undo all the progress made to control the pandemic. On Friday, the World Health Organisation urged more effort to detect new variants. The US Centres for Disease Control (CDC) said a new version first found in the United Kingdom may become dominant in the US by March. Despite not causing severe illness, it will lead to more people being hospitalised because it spreads so quickly. "We're taking it really very seriously," Dr <a rel="noopener" href="https://www.9news.com.au/world/coronavirus-us-anthony-faucci-receives-vaccine/495cd851-a3bf-4244-93da-720b0b5cbd1f" target="_blank">Anthony Fauci</a>, the US government's top infectious disease expert, told NBC on Sunday. "We need to do everything we can now ... to get transmission as low as we possibly can," Harvard University's Dr Michael Mina said. "The best way to prevent mutant strains from emerging is to slow transmission." Currently, vaccines are proving to be effective, but there are some signs that the new mutations may undermine tests for the virus and reduce the efficacy of antibody drugs as treatments. "We're in a race against time" because the virus "may stumble upon a mutation" that makes it more dangerous, Dr Pardis Sabeti, an evolutionary biologist at the Broad Institute of MIT and Harvard, said. Younger people may be more relaxed when it comes to wearing masks and shunning crowds, as the current strain isn't detrimental to them, but Dr Sabeti warned "in one mutational change, it might". So what needs to be done? "We're seeing a lot of variants, viral diversity because there's a lot of virus out there," and reducing new infections is the best way to curb it, Dr Adam Lauring, an infectious diseases expert at the University of Michigan, said. Loyce Pace, who runs the nonprofit Global Health Council and is a member of President Joe Biden's COVID-19 advisory board, said the same precautions scientists have been advising all along "still work and they still matter". "We still want people to be masking up," she said on Thursday on a webcast hosted by the Johns Hopkins Bloomberg School of Public Health. "We still need people to limit congregating with people outside their household. "We still need people to be washing their hands and really being vigilant about those public health practices, especially as these variants emerge."

News

Our Partners

Over 60

News

Shop

Catalogues

Contests

Entertainment

Travel

Health

Lifestyle

Finance

Property

Games

Information

Keep up to date

Search

Got no COVID-19 symptoms? A gene mutation might be the reason

Genetic mutations slowly accumulated over a lifetime change blood production after 70 years of age

A genetic mutation makes some people need less sleep

New fears as COVID-19 UK variant mutates again

New coronavirus mutations on the rise

Our Partners