Changes in microbiome in patients with Ichthyosis Vulgaris.

Ichthyosis vulgaris is the most common genetic cause of a disturbed
keratinisationproces of the skin. Loss-of-function mutations in the gene
encoding for filaggrine causes ichthyosis vulgaris. The exact mechanism in
which these mutations lead to development of ichthyosis vulgaris is not
entirely clear.
60-70% of patients with ichthyosis vulgaris also suffer from atopic dermatitis.
Recent research has shown that filaggrin mutations are responsible for 10-15%
of cases of atopic dermatitis. Both disease have in common that they are
associated with a change in barrier function of the skin.

It is known that microbes have the potential to make changes in the barrier
function of the skin. Recent developments in molecular biology made it possible
to analyse the microbiome on human skin. Several skin diseases are associated
with changes in the microbiome. Analysis of the microbiome of patients with
atopic dermatitis and psoriasis have already been done. The relation between
atopic dermatitis and filaggrin mutations has not yet been investigated.
Possibly, there exists a association between the microbiome and ichthyosis
vulgaris. Studies in mice already gave clues for such an association, as
changes in microbiome where observed in mices with a matriptase-deficiency (a
protease responsible for the conversion of profilaggrin to filaggrin.)
In this research we want to collect material to investigate this hypothesis.

The objective of this study is to analyse the microbiome of the skin of
patients with ichthyosis vulgaris (FLG -/-). This microbiome will be compared
to the microbiome of healthy volunteers (FLG +/+) and first grade family
members of patients with ichthyosis vulgaris (FLG +/-).
We hope to get clues of the role of micro-organisms in this disease. Insights
in the variations in microbiome in patients with ichthyosis vulgaris and atopic
dermatitis can contribute to the development of more specific targeted
treatments.
Also, we want to collect keratinocytes of patients with ichthyosis vulgaris.
These collections can contribute to further research in the skin barrier
function.

This is a small scale study with a pilot character. This study can lead to a
bigger cohort study, for example in patients with atopic dermatitis. We want to
approach 50 patients with ichthyosis vulgaris to collect material for genetic
and celbiologic research. This material will consist of collection of sputum, a
swab of the throat, skinswabs and 5 biopsies. This material will be analysed by
means of histologic investigation, DNA isolation, genotyping with PCR and
gel-electroforesis, immunohistochemic research and microbiome analysis.

The study will consist of the following groups:

1: Healthy volunteers (n=10)
2: Patients with ichthyosis vulgaris (n=50 approached, n=10 for final analysis)
3: First grade familiemembers of patients with ichthyosis vulgaris (n=10)

Analysis:
1. Genotyping of FLG status (Sputum DNA)
2. Histologic confirmation of diagnosis (Biopsies of Ichthyosis vulgaris
patients)
3. Microbiome analysis of skin and throat (Patients with Ichthyosis vulgaris
and their first grade family members)
4. Epidermal keratinocytes will be cultured for in vitro 3D skin cultures.

Group 1
Cells and DNA of this group is already in our database.

Group 2 and 3
Volunteers are recruted from our list and the list of patients and the list of
the Canisius Wilhelmina Hospital . Patients will receive an information letter
at home along with a declaration paper. A week later we will call the patient
and ask if he/she is willing to participate. If the patient is willing to
participate, he/she is invited in the UMC. St. Radboud. In the hospital an
anamnesis will be taken. Material will be collected in form of collection of
sputum, skin swabs, throat swabs and five 3 mm skin biopsies. DNA-analysis will
be performed according to standard methods.
Patients will recieve a travelfee based on use of public transportation and a
fee for collection of materials.

Patients will be asked to attend at the UMC St. Radboud. Here, the examinations
will take about 1-2 hours. Materials that will be collected consist of: 5 skin
biopsies, skin swab, a swab of the throath and sputum.
Biopsies can cause pain and discomfort and can cause scarring. Risk of
infection is minimal.