Association of ORMDL3, STAT6 and TBXA2R gene polymorphisms with asthma.

Asthma is one of the most common chronic diseases in childhood. It is well known that genetic variability contributes to asthma risk. One of the most replicated asthma candidate genes is ORM1-like 3 (Saccharomyces cerevisiae) (ORMDL3), which has been associated with childhood asthma susceptibility. Another asthma candidate gene is signal transducer and activator of transcription 6 (STAT6), a regulator of IgE class switching. Gene coding thromboxane A2 receptor (TBXA2R), involved in chronic airway inflammation, has been associated with asthma in several genetic studies. We have studied the association of polymorphism rs4795405 in ORMDL3, rs324011 in STAT6 as well as rs8113232 and rs3786989 in TBXA2R with asthma risk, various asthma phenotypes and asthma-related symptoms. The study group consisted of 154 children with asthma, in whom clinical parameters were measured and whose asthma control and atopic status were determined. A control group comprised 71 healthy children. Genotyping was performed using an allelic discrimination assay. The ORMDL3 polymorphism rs4795405 was suggestively associated with asthma risk. Furthermore, it was significantly associated with nonatopic asthma and asthma without rhinitis. No association was detected between the STAT6 polymorphism rs324011 or the TBXA2R polymorphisms rs8113232 and rs3786989 and asthma susceptibility. However, an association between rs324011 in STAT6 with recurrent wheezing in early childhood and a suggestive association between rs8113232 in TBXA2R with rhinitis in children with asthma were observed. Our results confirmed ORMDL3 as a candidate gene for childhood asthma susceptibility. STAT6 and TBXA2R polymorphisms were not associated with asthma risk, but they were associated with asthma-related symptoms.