Genome-wide approaches to the etiology of eczema

The present review summarizes the new discoveries in the genetics of eczema, focusing on the results from the recently published first genome-wide association study.

The first genome-wide association study for eczema included 10 000 individuals and provided strong evidence for a new susceptibility locus for eczema in chromosome 11q13.5 (P = 7.6 x 10). Importantly, this finding has been confirmed by an independent research group. Homozygous carriers of the risk allele rs7927894[A] represent 11% of the population and their risk of developing eczema is 1.47 times higher than in no-carriers. This polymorphism also confers risk to Crohn's disease, suggesting the locus may be related to epithelial immunity or differentiation. This study also detected association with the epidermal differentiation complex in 1q21 and suggests that additional risk factors exist in this region apart from the well established mutations in the filaggrin gene.

The first genome-wide association study for eczema has convincingly identified a new susceptibility locus for eczema. However, the exit from this study was limited, as only one new locus was identified. Complementary strategies aiming to distinguish the 'true-association' signals from the false positive results, together with larger sample sizes are required in order to achieve the full potential of this promising approach.