Scientists have discovered a gene that causes excess mucus in lungs, a major breakthrough which they claim could someday ease sufferings of people with chronic diseases like asthma or those fighting common cold.

Mucus is a sugar-coated collection of large proteins that, in healthy conditions, help the body defend itself by collecting and then clearing out contaminants.

Now, a team at Cincinnati Children’s Hospital Medical Center has identified a “transcription factor”, SPDEF, as the master gene which regulates a chain of dozens of downstream genes involved in mucus production.

SPDEF is an active player in other organ systems that need to produce mucus for normal function such as digestion.

In healthy lungs, however, the gene is mostly quiet as healthy lungs don’t produce excess mucus.

The scientists have also identified the beneficial lung cells, called Clara cells, which change their cell type to become goblet or mucous cells in a process - metaplasia.

According to them, the research sheds light on what has been a medical mystery - the precise biological reasons that the lungs in people with asthma, cystic fibrosis and other respiratory ailments clog with thick mucus.

Lead scientist Jeffrey Whitsett said that identifying the genetic circuits that cause mucous hyper-production gives potential targets for new therapies to moderate or stop it.

In fact, in their research, the scientists used an egg white protein called ovalbumin to induce an allergic reaction and inflammation in the lungs of laboratory mice. They found a a dramatic elevation in the expression of SPDEF in the lung tissues of the affected animals.

The animals also experienced hyper-production of thick mucus in their lungs. In rodents where SPDEF gene was switched off, inflammation and excessive mucus production didn’t occur, demonstrating the gene’s potential as diagnostic target. Mice lacking SPDEF were, however, unable to raise mucus production.

In mice where respiratory inflammation and excessive mucus production were present, the scientists found that SPDEF turned off genes involved in biological processes which help protect lung tissues from infection and damage.

Conversely, SPDEF activated genes that promote inflammation and excessive mucus - in particular FOXA3, AGR2 and mucins, revealed the findings published in the ‘Journal of Clinical Investigation’