Gene Linked to Deadly Fungal Infection
Findings support role of genetics in vulnerability to disease (October 21)
For most people, a fungal infection, such as athlete’s foot, means a simple trip to the drugstore. But in rare cases, fungal infections can spread below the skin’s surface and onto the lymph nodes, bones, digestive tract, or even the brain.
Researchers at Rockefeller University in New York City and at Necker Medical School in Paris have discovered a genetic deficiency that allows fungi to spread in this way — a condition called deep dermatophytosis. Their work suggests why treatments for fungal infections sometimes fail, and it gives weight to a genetic theory of infectious diseases, which proposes that a single genetic defect can cause an otherwise healthy person to become severely ill from a minor infection — be it viral, bacterial, or fungal.
The researchers examined the genomes of 17 people who had deep dermatophytosis but were otherwise healthy — their immune systems were working well and should have been able to fight off the infection. The researchers focused on a particular gene, CARD9, because previous studies of other fungal infections had found a defect on this gene to be the cause. After sequencing the patients’ genomes, CARD9 was indeed found to be deficient in all of them.
The research, published in the New England Journal of Medicine, is the latest evidence that genetics play an important role in an individual’s ability to overcome infectious diseases.
“As we discover more of these single-gene, inborn immune-system defects, we can give susceptible individuals with a family history of the disease a chance to prevent it, through molecular diagnosis and genetic counseling, as well as targeted treatments that restore a poor immune response,” said lead investigator Dr. Jean-Laurent Casanova.
Source: Rockefeller University; October 21, 2013.