Scientists have long known that asthma and allergies, which are on the rise in children in the developed world, are caused by a combination of genetic and environmental factors.
What has stumped them, though, is which genes are responsible.
Now, in what is thought to be a scientific first, researchers at Johns Hopkins Childrens Center and the Johns Hopkins Institute of Genetic Medicine in Maryland have identified a genetic glitch they believe is at the root of a range of allergic disorders, from peanuts to pollen to bee stings.
As a result, the team is now investigating whether common drugs already widely prescribed for other conditions can halt or reverse allergic symptoms, including asthma, in animals.
This is a really huge breakthrough because we are finally getting at the root causes of these diseases, lead investigator Dr. Pamela Frischmeyer-Guerrerio, an immunologist at Johns Hopkins Childrens Center, said in an interview. That gives us a huge handle on how to develop new treatments.
According to researchers, the culprit is aberrant signalling abnormal communication between cells in a protein called transforming growth factor-beta. The protein, also known as TGF-beta, has widespread effects on the body, including the maturation of infants stomachs in a way that develops tolerances to common foods that might otherwise induce an allergic reaction, and prevents allergies in later life.
Disruptions in TGF-beta signalling does not simply nudge immune cells to misbehave, but appears to single-handedly unlock the very chain reaction that eventually leads to allergic disease, said Dr. Harry Dietz, a cardiologist at Johns Hopkins Childrens Center and senior investigator for the study.
The findings were published Wednesday in Science Translational Medicine.
Researchers became curious about the effects of TGF-beta over several years after noticing that patients with Loeys-Dietz Syndrome (named in part after the Johns Hopkins cardiologist) were more prone to allergies than most people. Loeys-Dietz is a rare condition marked by flimsy blood vessels and a dangerous stretching of the aorta that is caused in part by abnormal TGF-beta signalling.
Their study involved 58 children with Loeys-Dietz between the ages of seven and 20 with a history of allergies such as food allergies, rhinitis, eczema, asthma and gastrointestinal and esophageal allergic disease.
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Scientists discover a genetic glitch at the root of allergies