Non-syndromic ichthyosis [30 genes]

Ichthyoses are a heterogeneous group of hereditary disorders characterized by different patterns of skin peeling and hyperkeratosis. Some types are distinguished from others based on heredity data, clinical data, the presence of related findings, as well as histopathological changes. Non-syndromic forms of the disease would be those with a condition limited to the skin.

The main forms of non-syndromic ichthyosis with a genetic origin included in this service are:

• Ichthyosis vulgaris.
• X-linked ichthyosis.
• Congenital ichthyoses of AR inheritance: harlequin ichthyosis, classic lamellar ichthyosis (LI), non-bullous congenital ichthyosiform erythroderma (CIE).
• Keratinopathic ichthyoses: epidermolytic ichthyosis and ichthyosis bullosa of Siemens.
• Erythrokeratoderma.

• Ichthyosis vulgaris: 1 / 250 newborns (PMID: 16444271).
• X-linked ichthyosis: 1 / 2,000 – 1 / 6,000 male newborns (ORPHA:461).
• Congenital ichthyoses of AR inheritance: harlequin ichthyosis (1/1,000,000; ORPHA:457), classic lamellar ichthyosis (1 / 100,000-1 / 200,000; ORPHA:313), congenital non-bullous ichthyosiform erythroderma (1 / 200,000 – 1 / 1,000,000; ORPHA:79394).
• Keratinopathic ichthyoses: epidermolytic ichthyosis (1-9 / 1,000,000; ORPHA:312) and Siemens bullous ichthyosis (<1 / 1,000,000; ORPHA:455).
• Erythrokeratoderma: 1 / 2,000,000 (ORPHA:308166).

Because the genetic cause is known for a large number of forms of ichthyosis, we recommend the clinical diagnosis of ichthyosis to be followed by a genetic study in search of the origin of the disease. This specific panel is recommended when the diagnostic certainty of having ichthyosis is high and as long as it is not accompanied by extracutaneous manifestations that raise suspicion of a syndromic form of the disease.

The benefits of a genetic diagnosis in this context are aimed at closing the diagnosis and family genetic counseling, together with prognostic information available for the patient and their family.

Service indicated when a non-syndromic ichthyosis is diagnosed by a dermatologist.