Faulty Gene May Be At Root Of Allergies

By Amir Khan

A faulty genetic pathway may be to blame for a host of allergic disorders, according to a new study in the journal Science Translational Medicine. Researchers from John Hopkins Children's Center found that a genetic pathway linked to some connective tissue disorders plays a substantial role in the development of severe allergies -- but experts question whether the findings will help patients.

Researchers found that abnormal signaling by a protein called transforming growth factor-beta, or TGF-beta, disrupts the way that the body's immune cells respond to common foods and environmental allergens, giving researchers a glimpse into a potential cause for allergies for the first time.

"Although allergic diseases are known to have strong familial associations, our understanding of how genetic variants relate to specific dysfunction at the cellular level is often lacking," the researchers, led by Hal Dietz, MD, a cardiologist at Johns Hopkins Children's Center, wrote in the study.

Mutations in TGF-beta signaling are known for resulting in genetic conditions called Marfan and Loeys-Dietz diseases, which cause the aorta to stretch and can lead to deadly aneurysms, but researchers found that the mutation can also cause a disruption in immune cell function without causing any connective tissue disorders.

"Disruption in TGF-beta signaling does not simply nudge immune cells to misbehave but appears to singlehandedly unlock the very chain reaction that eventually leads to allergic disease," Dr. Dietz said.

But while the findings indicate a potential cause for allergies, it's not likely to result in any new treatments, said Carla Davis, MD, director of food allergy program at Texas Children's Hospital.

"These kinds of studies really don't have a huge effect on the treatment at this time," Dr. Davis said. "It gives us more information on who might develop allergies, but it doesn't change how we treat them."

In addition, the cause of allergies is likely far more complicated than this one pathway, Davis said.

"Genetics can play an important role," she said, "but it's typically the combination of having a particular genetic background and being in environment that can express how that background is expressed in everyday life. We know that some environmental factors, like diet or smoking, can affect the expression of allergies in patients."

However, Davis said that studies like these are important for helping doctors get a better picture of who develops allergies, and why.

"It does speak to the fact that genetic mutations and alterations can change the expression of allergic diseases," she said. "But it's probably not the genes themselves that are playing a role, but the interaction between the gene and the environment."

"Faulty Gene May Be at Root of Allergies, Study Finds ^[4] " originally appeared on Everyday Health.