Ichthyosis vulgaris met populatiespecifieke filaggrine (FLG) mutaties

Filaggrin (‘filament-aggregating protein’) plays an essentialrole in the terminal differentiation of the epidermis.It forms an important barrier function of the skin preventingtransepidermal water loss and penetration ofallergens into the skin. The human profilaggrin geneconsists of three exons, located on chromosome 1q21. Atpresent, 85 unique filaggrin mutations are described inthe literature. Especially the West-European and Asianpopulation have been subject to investigation. There is aclear distinction in the spectrum of filaggrin mutationsbetween different ethnic populations. Therefore knowledgeof a patient’s ancestry is very important for genetictesting. Homozygote and compound heterozygote mutationscause a relatively severe phenotype of ichthyosisvulgaris. Heterozygote mutation carriers generally showa milder form of ichthyosis vulgaris. Patients with atopicdermatitis and a fillagrin mutation are significantly youngerand have a relatively more severe eczema with anincreased incidence of secondary infection. We present apatient with an extensive eczema and secondary bacterialimpetiginisation. Mutational analysis using NGS (NextGeneration Sequencing) and smMIPs (single moleculeMolecular Inversion Probes) revealed two pathogenicfilaggrin mutations: c.6950_6957del8 and c.7945delA