'First breath' gene identified

US scientists have identified a key gene that makes a baby's first breath possible. The researchers, based at the Cincinnati Children's Hospital Medical Center, say that the Foxa2 gene is a 'master' gene, which allows the lungs of a fetus to grow and develop properly. 'It was surprising to us that a single gene was able to orchestrate so many other aspects of lung function we know are critical for survival at the time of birth', said team leader Jeffrey Whitsett. The findings, published in the Proceedings of the National Academy of Sciences, could lead to better treatment for premature babies with lung problems, as well as children and adults with lung disorders.

It has long been suspected that Foxa2 plays a key role in lung development, but previous attempts to test this in animals failed, because 'knocking out' the gene completely causes embryos to die early in development. In the latest study, the scientists switched off the Foxa2 gene in mice foetuses that were almost fully developed, but before their lungs had matured. They found that the animals developed symptoms of respiratory distress syndrome, and nearly all died within hours of birth. The few that did survive went on to develop symptoms of asthma and the lung disease emphysema.

The team think the work shows that Foxa2 makes a protein that controls another set of around 55 genes, which trigger production of surfactant: a substance that prevents the airways of the lungs from collapsing, and allow the lungs to open when the newborn infant starts to breathe. 'Foxa2 turns out to regulate all the 'I'm going to be born' genes', said Whitsett. Very premature babies often do not have enough surfactant lining their lungs, as the lungs do not mature until the last three months of pregnancy.

Whitsett said: 'The discovery of this gene and understanding of how it works could lead to new treatments for premature infants and for children and adults who suffer from lung disease or injury'. Currently, premature babies are given artificial surfactants, but it might eventually be possible to develop ways of activating Foxa2 to trigger the body's own supply of this vital substance. 'Genetics is an exciting and vitally important area of respiratory medicine', Richard Russell of the British Thoracic Society told BBC News Online. He also called for more funding for genetic research into lung diseases, to help 'identify genetic problems and develop new treatment approaches for lung disease in the future'.