Cystic fibrosis is a genetic disease, it is therefore transmitted only from parents to their children. The disease is on chromosome 7, and as it is transmitted in a recessive way, it is necessary that the two parents carry the defective gene. To be carrying gene means of two genes to have reached one. If the two parents carry it, they have one chance out of four to have a child who has inherited it. Moreover, half of their offspring will be carrying the disease, even if it does not show. In Europe, a newborn baby out of 2000 develops it, and one person out of 20 carries the disease. Thanks to the progress already carried out in the field of remedies against the cystic fibrosis, one achieves now at an exceptional expectancy. Now most patients live over 31 years of age. Cystic fibrosis is due to an anomaly in the cells producing mucus. It blocks the respiratory tracts and unlike the mucus of a healthy person, it does not make it possible to evacuate dust and pathogenic agents.
For more than sixty years, studies were carried out on this disease, which condemns - almost - everybody who suffers from it. Already in 1938 at the university of Columbia Dorothy Andersen described the symptoms of cystic fibrosis and the anomalies due to this disease with precision. In 1946, one started to study the hereditary factors of cystic fibrosis. But it's only in these ten last years that one has made fulgurating progress by discovering a method to identify genes.