The Wiskott-Aldrich syndrome gene as a candidate gene for atopic dermatitis.

Atopic dermatitis is a multifactorial disorder probably caused by environmental factors in combination with susceptibility genes. The clinical similarity between atopic dermatitis and the eczema manifestation in patients with Wiskott-Aldrich syndrome made the previously identified WAS gene in chromosome sub-band Xpl 1.23 an interesting candidate gene for atopic dermatitis. We studied linkage and association to the WAS gene region using four polymorphic microsatellite markers in 406 Swedish families with at least two siblings affected with atopic dermatitis (in total 1514 individuals). In the analyses, we studied two qualitative traits: atopic dermatitis and elevated allergen-specific serum IgE antibodies, and one quantitative trait, a severity score of atopic dermatitis. We found that the marker MAOB gave positive linkage with a maximum lod score of 1.68 (p<0.05) to the severity score of atopic dermatitis. Association could not be seen to atopic dermatitis nor to elevated allergen-specific serum IgE antibodies in this region using the transmission disequilibrium test. Our results indicate that either the WAS gene or another gene in the area contributes to the severity of atopic dermatitis.