In some cases, an allele (part of a gene) found to be a higher risk factor for allergic asthma in some individuals may be associated with less risk of developing asthma in others. Dr. Martinez names the CD14 gene as one such example. When people with a variant of this gene are exposed to high levels of endotoxin (a product present in bacteria), it protects them from developing an allergic response. But people with this same gene variant who are exposed to low levels of endotoxin are at higher risk of an allergy.

Research to indentify and understand the genes related to asthma is ongoing.

"We have identified many genetic variants associated with asthma and allergies," said Dr. Marteniz. "However, only a fraction of the variants have been discovered. A lot of work still needs to be done to uncover how these diseases are inherited."

Dr. Martinez suggests that the expectation that doctors will someday be able to predict asthma at birth should be replaced with an expectation that experts will be able to identify which children should or should not be exposed to certain environmental factors to lessen their risk of developing asthma.

"The hope is that by combining information on genetic markers and exposures, we will be able to identify even more accurately children at high-risk for different forms of asthma in the future," he said.

acaai/