Estimates of the heritability of asthma are as high as 70% (CCJM, 2012).
The fact that some gene variants contribute to early-onset asthma but not later-onset asthma may point out that asthma is not one disease but several different conditions.
"Since early-onset asthma and late-onset asthma have distinct genetic underpinnings, they are likely to result from distinct pathobiologic mechanisms," Dr. Demenais and colleagues wrote.
Human chromosomes (grey) capped by telomeres (white). Image source: Wikipedia, public domain.
There is a growing consensus that "asthma is not one disease but merely the clinical manifestation of several different disease entities."
Genetics of Asthma Suggest It Is Umbrella Term for Multiple Diseases. John Gever, Staff Writer, MedPage Today.
Bouzigon E, et al "Effect of 17q21 variants and smoking exposure in early-onset asthma" N Engl J Med 2008; DOI: 10.1056/NEJMoa0806604.
Consumer genomics company 23andMe now tests for hay fever, and atopic dermatitis. Clinical relevance is unclear.