Final Activity Report Summary - GENETICS OF ALLERGY (Characterization of the genetic basis of Atopic Dermatitis.) We successfully performed the first genome-wide association study for atopic dermatitis reported to date. This study included 10 000 individuals and provided strong evidence for a new susceptibility locus for eczema on chromosome 11q13.5 (P = 7.6 x 10-10). Homozygous carriers of the risk allele rs7927894[A] represented 11 % of the population and their risk of developing eczema was 1.47 times higher than in non-carriers. Our study also detected association with the epidermal differentiation complex in 1q21. The loss-of-function mutations in the filaggrin gene, which was located in this gene cluster, were the best replicated atopic dermatitis susceptibility factor to date. Importantly, our data suggested that, apart from filaggrin mutations, additional risk factors existed in this extremely interesting cluster of genes involved in skin differentiation. These results were published in Nature Genetics in 2009. We also isolated peripheral blood mononuclear cells (PBMCs) from 210 individuals and generated genome-wide ribonucleic acid (mRNA) expression and single nucleotide polymorphism (SNP) data in order to detect the genetic factors determining the gene expression levels. We finally used this data set to identify genetic markers which increased disease risk and additionally affected gene expression levels.