Genetics of upper and lower airway diseases in the horse.
Authors: Gerber V, Tessier C, Marti E
Journal: Equine veterinary journal
Summary
# Genetics of upper and lower airway diseases in the horse Respiratory conditions in horses—including guttural pouch tympany, recurrent laryngeal neuropathy, recurrent airway obstruction (RAO), and exercise-induced pulmonary haemorrhage—demonstrate clear hereditary components, yet their expression depends heavily on complex gene-environment interactions rather than single-gene inheritance patterns. Gerber, Tessier and Marti's 2015 review synthesises evidence that these airway diseases are polygenic, meaning multiple genetic variants across several genes contribute to disease susceptibility; this polygenic architecture makes individual genetic tests unlikely to be clinically predictive or diagnostically useful in isolation. Chromosomal regions associated with guttural pouch tympany, recurrent laryngeal neuropathy, and RAO have been mapped, though causative variants remain largely unidentified. Rather than relying on single-gene testing, the authors propose that genetic profiling panels—combining assessment of multiple genetic risk factors with evaluation of environmental stressors (such as housing, dust exposure, and training intensity)—may prove more valuable clinically, though considerable research is needed to identify diagnostically useful markers. For practitioners managing genetically predisposed horses, this underscores the importance of environmental optimisation as a modifiable strategy to reduce disease expression, whilst recognising that breeding decisions cannot yet be reliably informed by genetic testing alone.
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Practical Takeaways
- •Do not expect single genetic tests to reliably diagnose or predict equine airway diseases; genetic risk must be assessed alongside environmental factors and management practices
- •Family history and individual genetics should inform breeding decisions, but environmental control (dust, ammonia, exercise management) remains critical for disease prevention
- •Emerging genetic profiling panels may eventually help identify high-risk individuals, but these tools are not yet clinically validated—consult current research before adoption
Key Findings
- •Genetic predispositions are well documented for guttural pouch tympany, recurrent laryngeal neuropathy, and RAO in horses
- •Equine respiratory diseases with genetic basis are polygenic, resulting from complex interactions between environment and multiple genes
- •Single gene tests are unlikely to be diagnostically useful; genetic profiling panels combining multiple factors may have greater clinical value
- •Chromosomal regions associated with guttural pouch tympany, recurrent laryngeal neuropathy, and RAO have been identified, but causative variants remain to be determined