Recent studies have identified 2 loss-of-function variants, R501X and 2282del4, in the filaggrin gene as predisposing factors in the development of eczema. In this study, representing the first analysis of the variants in a Swedish population, we analysed transmission in 406 multiplex eczema families with mainly adult patients. In accordance with previous studies we found association between the filaggrin gene variants and atopic eczema (p=9.5 x 10(-8)). The highest odds ratio for the combined allele, 4.73 (1.98-11.29), p=3.6 x 10(-8), was found for the subgroup with a severe eczema phenotype, and association was also found with raised allergen-specific IgE, allergic asthma and allergic rhinoconjunctivitis occurring in the context of eczema. Our results support an important role for the filaggrin gene variants R501X and 2282del4 in the development and severity of atopic eczema and indicate a possible role for the subsequent progression into eczema-associated phenotypes.