Previous studies have provided evidence for an association between filaggrin, a protein involved in the aggregation of keratin filaments in the skin, and diseases such as ichthyosis vulgaris and atopic dermatitis (AD). A Danish pediatric prospective study revealed that 63% of carriers of a function loss mutation in the filaggrin gene developed AD within one year. Further research revealed that 1 of 10 people of European origin carry 1 filaggrin null mutation, and they have only 50% of the normal amount of filaggrin protein in the skin and have dry skin and/or mild ichthyosis vulgaris and a high risk of AD. Furthermore, 1 of 400 people of European origin carry ...