In case you need a refresher, asthma is a lung condition that inflates the airways and causes shortness of breath, chest tightness and coughing. Asthma is a disease that affects people of all ages, but it most often starts in childhood. It's been estimated that 20 million people in the United States suffer from this disease.
Environmental factors are the main (but not the only) cause of asthma. Researchers at the Yale School of Medicine and the University of Chicago teamed up to see if there's genetic basis to asthma. Their study published in the "New England Journal of Medicine" shows
that genes could play a bigger role in asthma than previously thought. Many labs are now trying to figure out the genetics of asthma.
The team from Yale and Chicago conducted tests on 632 individuals from South Dakota - all of them related through multiple lines of descent. They are basically from a genealogy tree with 13 roots. Researchers explained:
"The small number of founding genomes reduces genetic differences and their communal lifestyle ensure that non-genetic factors are uniform among individuals,"
They discovered a variant in the CHI3L1 gene that codes for an enzyme called YKL-40. This protein is involved in the body's immune response, particularly against a substance known as chitin, which is found in many insects, such as house dust mites. The scientists noticed that YKL-40 levels were raised in the blood of people with asthma. This was correlated with a single nucleotide change in the CH13L gene. The assumption being that the minor genetic change raises enzyme levels and this somehow contributes to asthma.
In another study researchers from The Children's Hospital of Philadelphia and the University of Pennsylvania School of Medicine think that a particular gene variant raises the risk for childhood asthma in European and white American children, but does not do anything for African American children.
Following up on a study from 2007, that identified the ORMDL3 gene as a factor for childhood asthma among German and British children, researchers have used the largest pediatric genotyping program in the world (the one at Children's Hospital's Center for Applied Genomics in Philadelphia) to study more than three thousand white children and almost four thousand African American children.
They found that the existence of this same gene in white American children increases the risk of developing asthma by up to 70%. Although they don't know how this is done.
It is likely that several genes will be involved in the development of asthma and their identification will be a boon to modern medicine. It may one day become possible to develop personalized treatments that are tailored to an individual's genetic makeup.