Genetic influences on Asthma Severity.

In recent years asthma-related morbidity and mortality has increased globally. In the northern area of Spain the average total annual asthma–derived cost was estimated at US$2,879 per patient with costs increasing according to the grade of severity to as much as US$ 6,393 per patient in the case of severe asthma [1]. Given the social and economic impact of severe asthma, it is essential that the underlying determinants of asthma severity are understood. It is well established that there is a strong genetic component underlying susceptibility to asthma, but few studies have addressed whether there are genetic factors that modify severity of disease. While there is some evidence that severity of asthma is heritable, and association between measures of severity and polymorphism in candidate genes have been identified, the identification of genetic factors contributing to asthma severity has been hampered by the lack of clear, easily applied, accurate phenotype definitions for asthma severity that distinguish between underlying severity and level of therapeutic control. The development of such phenotypes in conjunction with more extensive studies of the genetics of asthma severity may allow identification of at risk individuals, and targeting of prophylactic therapy.