What causes long Covid-19? Researchers may have found the guilty gene

The first genome-wide study to identify genetic risk factors for long Covid-19 has led researchers to a DNA sequence near a gene called FOXP4, which is active in the lungs and in some immune cells, according to a report by Nature.

Long Covid-19 is a condition that can cause persistent symptoms after a person has recovered from Covid-19.

Global Covid-19 Host Genetics Initiative

The Global Covid-19 Host Genetics Initiative has been studying DNA sequences linked to a higher risk of developing severe Covid-19 for over three years. This research has identified genes involved in the immune system and in allowing the SARS-CoV-2 virus to enter cells.

The long-Covid-19 study is an offshoot from this research, according to Hugo Zeberg, a geneticist at the Karolinska Institute in Stockholm and a lead author of the preprint.

The study analysed data from 6,450 people with long Covid-19 across 16 countries. The researchers hope that this analysis will be just the beginning, as a vast amount of data is needed to understand a disorder as complex as long Covid-19, which has been associated with more than 200 symptoms, including severe fatigue and difficulties with focus and memory.

Such studies will lead to a deeper understanding of the causes of long Covid-19, Stéphanie Longet, an immunologist at Jean Monnet University in Saint-Etienne, was quoted as saying. She added that if the causes of long Covid-19, which may be multifactorial, are clearly understood, it will help treat patients more susceptible to developing long Covid-19 and potentially prevent long Covid-19.

Researchers compiled data from 24 studies involving a total of nearly 6,500 people diagnosed with long Covid-19, as well as more than one million other participants who served as controls to analyse the condition.

FOXP4

In an analysis that combined data from 11 studies, scientists found a particular DNA segment associated with about 1.6 times higher chances of developing long Covid-19. The particular region of the genome is located near a gene called FOXP4, which is active in the lungs and other organs.

Previous research has linked the gene FOXP4 to an increased risk of severe Covid-19. Zeberg and the team of researchers concluded that the contribution of the DNA variant to long-Covid risk is too large to be explained by its link to severe Covid-19 alone.