Umweltbedingte Erkrankungen - Auf der Suche nach Allergie-Genen

In Search of Allergy Genes

Spring and sommer: trees, bushes and grasses are in bloom. For about 15 percent of Germans a pollen allergy or hay fever takes much of the pleasure out of this beautiful time of year. The incidence of these and other allergies is increasing. Almost everyone knows someone in the family or circle of friends who has hay fever or asthma. Perhaps even you are affected by an allergy.

Children are especially susceptible to allergies. In Germany approximately 8 to 10 percent of children 10 years of age are affected by asthma, and a similar number suffers from hay fever.

Recently, researchers of the National Genome Research Network (NGFN) have discovered an important gene for the development of allergy. The gene is named CARD 15 and carries the blueprint for a protein that maintains the defense against bacteria in the cells of the mucosa.

Three genetic variants of the gene for CARD 15 exist in the population.

Dr. Michael Kabesch and his team from the University of Munich have studied 1,872 children and found out that these genetic variants increase the risk for an allergy considerably.

The genetic text of the CARD 15 gene has only undergone a minor change. A swap of a single gene letter –"G" for "C" is sufficient to increase threefold the risk of getting hay fever. Furthermore, the probability of developing an allergic skin reaction is twice as high for affected children compared to those carrying the healthy, non-mutated variant of the gene.

The general risk of developing oversensitivity towards certain substances increases by 50 percent if an additional "C" is included in the CARD 15 gene. The error in the blueprint results in a shortened CARD 15 protein which can no longer fend off the bacteria which have settled in the bowel. The consequence is a chronic inflammation.

Genetic alterations in the CARD 15 gene are also involved in the development of the chronic inflammatory bowel disease called Crohn’s disease.

"Within the next few years the results of these studies might contribute to new insights on the cause of hay fever and other allergies. The results might also aid the development of assays designed to improve diagnosis," said Professor Michael Kabesch, head of the NGFN studies on allergy research.