Gene Variant in Boys Linked to Higher Risk of Severe Post COVID Inflammatory Syndrome
Nikhil Prasad Fact checked by:Thailand Medical News Team Sep 08, 2025 3 hours, 3 minutes ago
Medical News: A Genetic Risk Factor Emerges
Scientists from Instituto René Rachou Fiocruz Minas, Universidade Federal de Minas Gerais, Hospital Infantil João Paulo II, and the Laboratório de Vírus at Universidade Federal de Minas Gerais have uncovered a genetic clue that may explain why some boys develop life-threatening inflammatory complications after COVID-19. Their research focused on the TLR7 rs179008 T allele, a variant found on the X chromosome, which appears to increase the risk of multisystem inflammatory syndrome in children (MIS-C) and Kawasaki-like disease following SARS-CoV-2 infection. In the midway of this
Medical News report, it becomes clear that this discovery could pave the way for better detection and treatment strategies for children most at risk.
Gene Variant in Boys Linked to Higher Risk of Severe Post COVID Inflammatory Syndrome
What the Study Found
The team analyzed 73 hospitalized children under the age of 13 who had confirmed COVID-19 between 2021 and 2022. Among them, 8 developed MIS-C and 4 developed Kawasaki-like syndrome. Boys were far more vulnerable, with three times the incidence compared to girls. Alarmingly, all four deaths recorded in the study occurred in boys, three of whom had MIS-C. One of the boys who died carried the TLR7 T allele, hinting at a dangerous connection.
The study showed that boys carrying the T allele were nearly twice as likely to develop MIS-C or Kawasaki-like syndrome compared to other infected children. They also faced a 1.75-fold higher risk of severe or critical illness requiring intensive care. The T allele was 2.6 times more frequent in children who developed these post-COVID complications than in those who did not.
Why the TLR7 Variant Matters
TLR7 is a receptor that helps the immune system recognize viral RNA and quickly launch an antiviral defense. In boys, who carry only one copy of the X chromosome, the presence of the T variant can significantly weaken this immune response. This impairment delays the body’s ability to control the virus, leading to prolonged infection and, eventually, uncontrolled inflammation. Such a runaway immune reaction can damage multiple organs, explaining the severe outcomes seen in MIS-C and Kawasaki-like disease.
Broader Implications for Children
The findings help explain why MIS-C is more common and more deadly in boys. While most children recover from COVID-19 with mild or no symptoms, those with genetic vulnerabilities such as the TLR7 variant may face life-threatening consequences. The study suggests that genetic testing for TLR7 mutations could be developed as a tool for identifying high-risk children early on, allowing doctors to intervene before severe inflammation sets in.
Conclusion
This research highlights the critical role of genetics in shaping COVID-19 outcomes in children. The discovery that a single gene variant nearly doubles the risk of severe MIS-C in boys underscores the need for persona
lized medicine approaches in pediatric care. By understanding which children are genetically predisposed, health systems could focus resources on monitoring and protecting those most vulnerable. Ultimately, this could save lives and prevent tragic complications.
The study findings were published in the peer reviewed International Journal of Molecular Sciences.
https://www.mdpi.com/1422-0067/26/17/8491
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https://www.thailandmedical.news/news/genetic-variants-in-detox-enzyme-could-explain-long-covid-and-severe-sars-cov-2-cases
https://www.thailandmedical.news/news/covid-19-news-study-finds-that-variants-of-mbl2-gene-that-are-associated-with-high-mannose-binding-lectin-levels-are-protective-in-covid-19
https://www.thailandmedical.news/news/genetic-variants-and-covid-19-the-association-of-crp-gene-rs1205-with-disease-severity
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