Genodermatoses

Genodermatoses

Genodermatoses mean skin diseases related to genetics.
Ichthyosis: means dry and scaly skin. This term is derived from Greek word ichthys, meaning (fish).

Types of ichhthyosis:
Ichthyosis vulgaris. 1.
2.X-linked ichthyosis.
3.Epidermolytic hyperkeratosis (Bullous congenital ichthyosiform erythroderma), Autosomal dominant .
4. Autosomal recessive ichthyosis: non- bullous congenital ichthyosiform erythroderma& lamellar ichthyosis.
5. Harlequin ichthyosis, Autosomal recessive.
6.Erythrokeratodermia variabilis , Autosomal dominant .
7. Ichthyosis Linearis circumflexa, Autosomal recessive.


Inheritance: Autosomal dominant .
Incidence:1:250.
Onset: Early childhood ,usually between 3-12 months of age .
Scales: fine ,brany scales, pasted –on over the entire body.
The scales are coarser on the lower extremities than they are on the trunk .
Varying degrees of dryness of the skin may be evident .
Distribution: the extensor surfaces of the extremities are most prominently involved .The flexures (axillary,gluteal folds,antecubital and popliteal fossae) are usually spared.
Accentuated skin markings and hyperkeratosis of the palms are common features.
Associated features: Atopy and keratosis pilaris.
Histopathology: hyperkeratosis and absence of granular layers.
Natural course: The patient improves in summer and gets worse in winter .