A genetic mutation causes serious infections in Inuit, a study has found

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

According to the professor of immunology and specialist in infectious diseases at Aarhus University on the east coast of the country, doctors could not figure out what was wrong with him. They then contacted her to perform the genomic sequencing of the young patient.

The work of dr. Mogensen then revealed a mutation in the IFNAR2 gene.

It is a very important molecule for immune cells to defend against viruses.

By infecting the young patient’s cells with the measles virus and other virusesthey found that these multiplied rapidly and the host cells died. It means that something prevented them from fighting back against the aggression.

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

Photo: Jan Zeiss / Aarhus University

The medical team also learned that the infant had been vaccinated against measles, rubella and mumps two or three weeks previously.

By contacting doctors at newcastlein England, they found that they too had found the same mutation in patients.

We’ve found it to be fairly common among the Inuit of Canada, Alaska and Greenland. What these patients have in common is that they do not defend themselves very well against viral infections and live vaccines in which the virus is still present but weaker.

The peer-reviewed study was published in Journal of Experimental Medicine from 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 this data, the researchers were able to determine that the anomaly affected one in 1,500 people.

There could be dead children for a long time and we don’t know why 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, participated in the study remotely and shared data he collected during his career at Nunavik.

This geneticist has also extensively studied Inuit populations and found that this population is at greater risk of developing aneurysms. When he investigated the question, he and his team finally found that there were genetic variations here too.

We found a variant in a gene that seemed to be much more common in Inuit with aneurysms, so we think we’ve found a gene that predisposes to aneurysms in this population.explains Dr. Guy Rouleau.

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

The director of The Neuro, Dr. Guy Rouleau, studied a variant that predisposes Nunavik Inuit to developing aneurysms.

Photo: The Canadian Press/Paul Chiasson

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

We were able to identify enriched variants in this population and believe that they could be useful for this population to keep them healthy in their environment.

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

When you have such a high frequency with a mutation, it’s often because there’s an advantage to having it. It is possible that it has a positive effect on other diseases, we do not know at allsays dr Trina Mogensen.

Gather more data

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

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

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

A quote from dr Michael Patterson, Nunavut’s Chief Medical Officer of Health

He also believes more work needs to be done to determine how this genetic defect can lead to more serious complications than would be the case in the general population.

Its a lot 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 the study is worrying and that more research is needed.

Photo: CBC/Mike Zimmer

The Nunavik Regional Board of Health and Social Services also softened the study’s findings.

In an email, a spokesman recalled that the study involved five sick children, two of whom are from Nunavik.

This very small number does not mean that this is currently a significant problem. Even if there was a temporal relationship between vaccination and serious illness, this does not prove that one is the cause of the other.it is written.

Large-scale testing to prevent reactions

The last thing doctors want is to induce vaccination. To avoid this reaction, Dr. Mogensen believes it is important to test all babies at birth to determine if they carry the genetic abnormality.

If this is the case, in their opinion, it is sufficient not to give a live attenuated virus vaccine, but a vaccine such as the messenger RNA vaccine that does not contain small amounts of virus.

We have effective treatments when we know the cause is the vaccine. If we know what it is, we can treat it very early and get a good result. »

A quote from dr Trine Mogensen, study co-author and specialist in immunology and infectious diseases
Visualization of infected cells through a microscope.

Rubella infection in a patient’s cells. By infecting cells with certain viruses, the researchers found they couldn’t fight back and died.

Photo: Courtesy of Trine Mogensen

She believes such screening is feasible in Greenland, even among populations living in small, remote communities, since most births take place in hospitals. dr Patterson agrees with Nunavut.

dr Trine Mogensen believes that to continue this dynamic, it is necessary to identify more people carrying the mutation in the Inuit population, particularly by combing through the Greenland sample banks to confirm the frequency of the anomaly. She also believes it would be relevant to see if the mutation occurs elsewhere in the world and study the rare infections that would be linked.

However, the task promises to be difficult because, as Dr. Guy Rouleau remembers All population groups in the world are more susceptible to certain diseases.

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