Keratinisation disorders comprise a heterogeneous group characterised by abnormal epidermal differentiation, such as variants of ichthyosis and palmoplantar keratoderma.

Skin fragility disorders comprise a group of inherited blistering diseases, such as variants of epidermolysis bullosa.

Ectodermal dysplasias consists of multiple inherited disorders that are characterised by abnormalities of the embryonic ectoderm, such as hair, nails, sweat glands or teeth.

This group are genodermatoses associated with the development of malignancies ((non-)cutaneous), such as basal cell nevus syndrome (BCNS), Birt-Hoog-Dubé syndrome, tuberous sclerosis, etc.

In this group genodermatoses are listed that do not fit the other groups as mentioned above, for example albinism and cutis laxa.

Outcomes of reproductive options such as prenatal diagnostics (PND) and preimplantation genetic testing (PGT) will be assessed, looking at indications, decision-making by professionals and/or the Dutch national indication committee as to whether or not to start a PGT procedure. The results of PND and PGT, pregnancy outcomes (success rates) and risks (i.e. the risk of miscarriage) will be summarised. The percentage of continuing pregnancies from prenatal screening techniques (especially PGT) will be calculated. In addition, the percentage of affected embryos will be calculated for different genodermatoses per PGT cycle using using the following formula: (number of affected embryos)/(total number of embryos)*100%.