Danish physicians have identified a gene which causes hereditary Chronic Obstructive Pulmonary Disease (COPD). Screening children of COPD patients for the genetic defect could enable early treatment to help prevent loss of lung function. (Photo: Colourbox)

Smoker's lung gene discovered

Researchers have identified a hereditary genetic defect which increases the risk of Chronic Obstructive Pulmonary Disease (COPD).

Chronic Obstructive Pulmonary Disease (COPD), also known as smoker's lung, is one of the most frequent causes of death worldwide. COPD results in reduced lung function and can significantly impair life quality.

Although COPD is often caused by smoking, some people have a genetic predisposition to develop the disease.

Danish physicians have now identified one of the genes involved in the development of COPD, and this could lead to earlier diagnosis and treatment.

"COPD is usually first discovered late in life when the disease has already manifested itself. But we have identified a defective gene which causes the disease to develop," says Morten Dahl, of the Department of Clinical Biochemistry at Copenhagen University Hospital, who made the discovery together with a colleague.

COPD significantly reduces lung function

The severity of COPD is categorised according to loss of lung function:

  • Health people: lung function is around 100 percent of normal values
  • Mild COPD: lung function is around 80 percent of normal values
  • Moderate COPD: lung function is between 50 and 80 percent of normal values
  • Severe COPD: lung function is between 30 and 50 percent of normal values
  • Very Severe COPD: lung function is below 30 percent of normal values

This is the first identification of a gene linked to reduced function of the receptors that are important to airway musculature. These receptors are the same ones that are targeted by asthma drugs, and which are also used for COPD. The drugs relax the musculature around the airways and ease breathing.

According to the new research, the genetic defect increases the risk of developing COPD by 450 percent, and reduces the lung function by 7 percent.

Screening children for COPD

In families with parents who have hereditary COPD, physicians can now screen their children's genes to discover whether they have inherited the defect.

"Many people carry the defect for hereditary COPD. But for the disease to manifest itself, the defect must exist on both chromosomes,” says Dahl.

“If screening in children shows the defect on both chromosomes, one could perhaps initiate COPD medication at an early stage to help prevent the lung damage caused by COPD."

60,000 gene analyses

The research was conducted using two large population studies comprising a total of 60,000 people. Genetic material was screened for the hereditary variant of COPD and compared with blood samples and lung function tests. This led to the discovery of the connection between the genetic defect and COPD.

In addition to the treatment of hereditary COPD, the new discovery will also be used to expand the knowledge of COPD in general.

"COPD is the fourth most frequent cause of death in Denmark. WHO forecasts that this cause of death will increase worldwide in the future, especially in third world countries. 20 percent of all COPD patients are non-smokers, and here the hereditary factors are significant," says the researcher, adding that more studies are needed before a systematic gene test for hereditary COPD can be developed.

Read this story in Danish at videnskab.dk

Translated by: Nigel Mander

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