New York, Feb 4 (IANS): Scientists have identified a genetic flaw responsible for a rare form of inherited allergy induced by vibration.

Running, hand clapping, towel drying or even taking a bumpy bus ride can cause temporary skin rashes in people with this rare disorder, also known as vibratory urticaria.

By studying affected families, the researchers discovered how vibration promotes the release of inflammatory chemicals from the immune system's mast cells, causing hives and other allergic symptoms.

"This work marks, to the best of our knowledge, the first identification of a genetic basis for a mast-cell-mediated urticaria induced by a mechanical stimulus," said study co-author Dean Metcalfe from National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health.

The findings, published online in the New England Journal of Medicine, suggest that people with this form of vibratory urticaria experience an exaggerated version of a normal cellular response to vibration.

In addition to itchy red welts at the site of vibration on the skin, people with vibratory urticaria also sometimes experience flushing, headaches, fatigue, blurry vision or a metallic taste in the mouth.

Symptoms usually disappear within an hour, but those affected may experience several episodes per day.

The current study involved three families in which multiple generations experienced vibratory urticaria.

To identify the genetic basis of the disorder, the scientists performed genetic analyses, including DNA sequencing, on 36 affected and unaffected members from the three families.

They found a single mutation in the ADGRE2 gene shared by family members with vibratory urticaria but not present in unaffected people.

The scientists did not detect the ADGRE2 mutation in variant databases or in the DNA of more than 1,000 unaffected individuals with a similar genetic ancestry as the three families.