Ichthyosis vulgaris: novelFLGmutations in the German population and high presence of CD1a+ cells in the epidermis of the atopic subgroup

Summary Background Ichthyosis vulgaris (IV) is a genetic disorder with a prevalence of 1 : 250–1000 caused by filaggrin (FLG) mutations, which also predispose to atopic diseases. Objectives To study the genotype/phenotype relationship in IV and to analyse whether the suggested skin barrier defect is associated with differences of epidermal dendritic cells. Patients/methods We evaluated a cohort of 26 German patients with IV, established an IV severity score and analysed epidermal ultrastructure, histology, filaggrin and CD1a antigens. Mutations were screened by restriction enzyme analysis. Particular sequencing techniques allowed the complete FLG analysis to reveal novel mutations. Results The combined null allele frequency of R501X and 2282del4 was 67·3%. Patients also showed the mutations S3247X and R2447X as well as five novel FLG mutations: 424del17 and 621del4 (profilaggrin S100 domain), 2974delGA (repeat 2), R3766X (repeat 101) and E4265X (repeat 102). Their combined allele frequency in controls was