Ichthyosis vulgaris met populatiespecifieke filaggrine (FLG) mutaties

Filaggrin (‘filament-aggregating protein’) plays an essential
role in the terminal differentiation of the epidermis.
It forms an important barrier function of the skin preventing
transepidermal water loss and penetration of
allergens into the skin. The human profilaggrin gene
consists of three exons, located on chromosome 1q21. At
present, 85 unique filaggrin mutations are described in
the literature. Especially the West-European and Asian
population have been subject to investigation. There is a
clear distinction in the spectrum of filaggrin mutations
between different ethnic populations. Therefore knowledge
of a patient’s ancestry is very important for genetic
testing. Homozygote and compound heterozygote mutations
cause a relatively severe phenotype of ichthyosis
vulgaris. Heterozygote mutation carriers generally show
a milder form of ichthyosis vulgaris. Patients with atopic
dermatitis and a fillagrin mutation are significantly younger
and have a relatively more severe eczema with an
increased incidence of secondary infection. We present a
patient with an extensive eczema and secondary bacterial
impetiginisation. Mutational analysis using NGS (Next
Generation Sequencing) and smMIPs (single molecule
Molecular Inversion Probes) revealed two pathogenic
filaggrin mutations: c.6950_6957del8 and c.7945delA.