Background: Atopic dermatitis (AD) is caused by genetic and environmental factors that interact to determine disease susceptibility and severity. Several lines of evidence suggest that the IL-4 gene and the IL-4-receptor alpha (IL-4Ralpha) gene are involved in the development of atopic diseases.
Objective: The objective of this study was to evaluate the possible involvement of the chromosomal regions 5q31 and 16p12, which include the genes coding for the IL-4 and the IL-4Ralpha in AD.
Methods: We conducted linkage analysis and association studies using the microsatellite markers D16S298 and D16S403 and a single nucleotide polymorphism in the promoter region of the IL-4 gene (- 590C/T) in 406 Swedish families with at least two siblings affected with AD, in total 1514 individuals.
Results and conclusion: We report linkage (P < 0.005) to the - 590C/T polymorphism in the promoter of the IL-4 gene for the semiquantitative trait severity score of AD. Neither linkage nor association was found to the IL-4Ralpha chromosomal region.