The study was conducted on 4836 Japanese individuals which involved 1532 adult patients and 3,304 controls to clarify the genetic origins of adult asthma.

The researchers identified five genetic regions with susceptibility to adult asthma among 460,000 genetic variants (called Single Nucleotide Polymorphisms or SNPs), in which three were not previously connected to the disease.

The identified genetic regions contained SNPs previously associated with the FEV1/FVC ratio.

The ratio is calculated to the diagnosis of obstructive and restrictive diseases, as well as numerous genes that play a role in immunity response to infection and inflammation.

The SNP in the region encoding the protein thymic stromal lymphopoietin (TSLP) was studied on non-Hispanic individuals of European ancestry, suggesting that region may be a common hereditary factor for asthma across ethnic groups.