Linkage and association studies of atopy and the chromosome 11q13 region.

The clinical syndrome atopy is largely determined by genetic factors. In 1989, the first linkage of markers within and flanking the chromosomal region 11q13 and atopy was reported. In the following years, the gene coding for the beta chain of the high affinity IgE receptor was localised to this region and two polymorphisms in this gene have been shown to be associated with the atopic phenotype. We investigated two independent populations (population based and outpatient department) with different degrees of clinical symptoms. Using highly polymorphic markers we could find no evidence for linkage or allelic association of this particular genomic region to the atopic phenotype defined by enhanced IgE responsiveness (p>0.05). Neither did we succeed in finding either of the two polymorphisms described, nor could we identify any other polymorphisms within the gene. However, we found weak evidence for linkage in asthmatic sib pairs regarding maternal alleles (p=0.03). We conclude from our data that in our populations the gene for the beta chain of the high affinity IgE receptor is of minor importance for enhanced IgE responsiveness, and that it might influence atopy with clinical signs like asthma through maternally derived alleles.