Home LATEST NEWS HEALTH Gene mutation causes serious infections among Inuit, study finds

Gene mutation causes serious infections among Inuit, study finds

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It all started when a 20-month-old Inuk infant arrived from Greenland at a hospital in Copenhagen, Denmark, recalls Dr. Trine Mogensen.

According to this professor of immunology and doctor specializing in infectious diseases at the University of Aarhus, on the east coast of Denmark, doctors could not figure out what was wrong with this baby. They then contacted Dr. Mogensen to do the genomic sequencing of the young patient.

Dr. Mogensen’s work then revealed a mutation in the IFNAR2 gene.

It happens to be a very important molecule for immune cells to defend themselves against viruses.

By infecting the cells of the young patient with the measles virus and with other viruses, they found that these multiplied strongly and the host cells died. So that meant that something was preventing them from defending themselves against the aggressor.

Dr. Trine Mogensen smiles at the photographer.

Dr. Trine Mogensen, one of the study’s authors, believes screening babies is the key to detecting the genetic mutation and tailoring treatments.

Photo: Jan Zeiss / Aarhus University

The doctor’s team also learned that the infant had received the measles, rubella and mumps vaccine two or three weeks earlier.

By contacting doctors at Newcastlein England, they learned that they too had discovered the same mutation in patients.

We found that it is quite common among the Inuit of Canada, Alaska and Greenland. These patients have in common a rather precarious defense against viral infections and against live vaccines, in which the virus is still present, but in a weakened form.

This peer-reviewed study was published in the issue of Journal of Experimental Medicine of April 2022. It is based on the cases of five sick patients from Greenland, Canada and Alaska and on 5000 blood samples from other children from Nunavik and Greenland.

With these data, the researchers were able to determine that the anomaly affected one in 1,500 people.

Deaths of children could be happening for a long time already without knowing the reason, and it could be because of this mutation. »

A quote from Dr. Trine Mogensen, study co-author and specialist in immunology and infectious diseases

An anomaly that would protect against something else?

Dr. Guy Rouleau, now director of The Neuro, the Montreal Neurological Institute-Hospital, took part in this study from afar by sharing data he collected in Nunavik during his career.

This genetics specialist has also studied the Inuit populations extensively and realized that this population was at high risk of being struck by aneurysms. By taking an interest in this question, he and his team ended up discovering that there were genetic variations there too.

We found a variant in a gene that seemed to be much more common, significantly, in Inuit who had aneurysms, so we think we found a gene that predisposes to aneurysms in that population.explains Dr. Guy Rouleau.

The director of The Neuro, doctor Guy Rouleau, in a laboratory.

The Neuro’s director, Dr. Guy Rouleau, studied a variant that predisposes Nunavik Inuit to be struck by aneurysms.

Photo: The Canadian Press/Paul Chiasson

This research also allowed his team to determine that the Inuit of Nunavik are closer to the Inuit of Greenland than to other Inuit and that the population is homogeneous, since there has been little mixing with other populations.

We have been able to discover enriched variants in this population and we think that they may be useful to this population to keep it healthy in its environment.

The hypothesis of scientists, both Dr. Rouleau and Dr. Mogensen, is that these variants, these genetic abnormalities, are indeed there for a reason.

Often, when you have such a high frequency with a mutation, it’s because there’s an advantage to having it. It is possible that it has a positive effect against other diseases, but we do not know at all for the momentsays Dr. Mogensen.

Collect more data

While the question remains unanswered, researchers know that such a discovery will require much more research.

So too does Dr. Michael Patterson, Nunavut’s Chief Medical Officer of Health, who judges the study worrying. He would like to have more data.

The study itself does not provide enough information to know the frequency of this infection among Inuit or in the general population. »

A quote from Dr. Michael Patterson, Nunavut Chief Medical Officer of Health

He also thinks that more work needs to be done to determine how this genetic defect can lead to more serious complications than might be seen in the general population.

There is still a lot of work to dohe believes.

Nunavut's Chief Medical Officer of Health, Dr. Michael Patterson, at a press conference.

Nunavut’s Chief Medical Officer of Health, Dr. Michael Patterson, believes this study is concerning and that more research is needed.

Photo: CBC/Mike Zimmer

The Nunavik Regional Board of Health and Social Services also puts the results of the study into perspective.

In an email, a spokesperson recalls that this study concerns five sick children, including two who are from Nunavik.

This very small number does not allow us to conclude that this is a serious problem at the moment. Also, even if there was a temporal association between a vaccination and serious illness, it does not prove that one is the cause of the other.we write.

Large-scale testing to prevent reactions

What doctors want to avoid at all costs is triggering vaccine anxiety. To avoid this reaction, Dr Mogensen thinks it is crucial to test all babies at birth to see if they carry this genetic abnormality.

If this is the case, it would be enough, according to her, to administer not vaccines with live attenuated viruses but rather vaccines like the one with messenger RNA, which does not contain small quantities of virus.

We have effective treatments if we know that the vaccine is involved. If we know what it is, we can start the treatment very early and get a good result. »

A quote from Dr. Trine Mogensen, study co-author and specialist in immunology and infectious diseases
Representation of infected cells observed by microscope.

Rubella infection in the cells of a patient. By infecting cells with certain viruses, the researchers realized that they were unable to defend themselves and died.

Photo: Courtesy of Trine Mogensen

She believes that in Greenland, such screening is feasible, even among populations who live in small, remote communities, as most births take place in hospitals. Dr. Patterson agrees with Nunavut.

To continue this momentum, Dr. Trine Mogensen thinks it is necessary to identify more people carrying the mutation among the Inuit population, in particular by going through the Greenland sample banks to check the frequency of this anomaly. She also believes that it would be relevant to check whether this mutation occurs elsewhere in the world and to study the rare infections that may be linked to it.

However, the task promises to be difficult: indeed, as Dr Guy Rouleau reminds us, all the populations of the world are more predisposed to have certain diseases.

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