An international team led by researchers from the University of Copenhagen studied the genes of 1,200 young Danish children aged between two and six who had been hospitalised several times because of severe asthma attacks, and compared them with 2,500 healthy people.
In addition to finding further evidence for four genes previously implicated as asthma susceptibility genes, the researchers identified a novel gene, CDHR3, which is particularly active in epithelial cells lining the surfaces of airways.
The study team then replicated their findings using data from other children of both European and non-European ancestry.
"Asthma researchers have been increasingly interested in the role of the airway epithelium in the development of asthma," said co-lead author of the study, Hakon Hakonarson, director of the Center for Applied Genomics at The Children's Hospital of Philadelphia (CHOP).
"Abnormalities in the epithelial cells may increase a patient's risk to environmental triggers by exaggerating immune responses and making the airway overreact.
"Because the CDHR3 gene is related to a family of proteins involved in cell adhesion and cell-to-cell interaction, it is plausible that variations in this gene may disrupt normal functioning in these airway cells, and make a child vulnerable to asthma," Hakonarson said.
"Our study supports the theory that asthma is not just a single disease, but a complex of several sub-types that should be genetically mapped and understood individually if we are to prevent and treat the disease properly in future," said Klaus Bonnelykke from the Copenhagen Studies of Asthma in Childhood (COPSAC), the Danish Pediatric Asthma Center, Copenhagen University Hospital.
The results have been published in the journal Nature Genetics.