Genetics of human asthma and equine recurrent airway obstruction: can these two diseases be compared?

Asthma in humans is a complex, atopic condition, influenced by environmental factors and a well-documented genetic component. Familial clustering has also been demonstrated for recurrent airway obstruction (RAO) in the horse, a disease which shares some similarities with human asthma. The human condition is well understood at the molecular level, with several of the genes involved characterised. However, very little is known about the potential genes involved in RAO, The human genome map has been completed and the positions of some of the genes involved in asthma have been localised to various chromosomes, and in particular to regions of chromosome 5. Comparison of this data with increasing knowledge of the horse genome map will produce candidate genes for RAO. The identification of genetic markers for RAO will enable the breeding of horses less susceptible to the disease, help in identifying animals at risk prior to the onset of symptoms and therefore allow the reduction of exposure to potentially disease-causing environmental factors, Finally, phormacogenetics techniques in which the genetic basis which contributes to a disease status are analysed and used to identify new or optimise existing treatments could also be applied to RAO, This review highlights parallels between the two diseases and suggests potential areas of human knowledge which may be exploited to elucidate the genetic component of RAO.