Is Asthma Genetic ?

Andrew:
We have a two-part e-mail question that comes from Mark in Illinois. First, how do people get asthma? And is there a genetic connection?

Dr. Shapiro:
The two questions are really connected. We believe that people get asthma because they have a genetic predisposition to having overly reactive muscles in the bronchial tubes and overly sensitive bronchial tubes. And then if people who have that genetic predisposition are exposed to certain things in their environment at certain critical times, the combination of genetics and environment causes asthma to occur.

These sorts of challenges to the system would be viral infections early in childhood, exposure to a lot of allergenic substances–we call them “allergens”–things like dust mites and pet dander, for example. If you’ve got the right genetic programming and you meet up with a lot of something your system is sensitive to, that seems to be the critical formula for asthma.

Andrew:
If my wife and I have asthma, does that mean for sure that my children will have asthma?

Dr. Shapiro:
The statistics are certainly in your favor. In general, people feel that if one parent is allergic, a child has something like a 30-35 percent chance of being allergic; possibly not with asthma, but with some sort of disease that could predispose them to asthma. iIf both parents are allergic, it’s up to about 65 percent. So yes, there is a link but it’s not an absolute penetrance for that asthma and allergy issue.