KLICK syndrome
Résumé
Erythrokeratoderma refers to a group of rareinherited disorders with both clinical and genetic hetero-geneities. Lesions usually start in infancy and are characterized by localized and well-demarcated erythematous andhyperkeratotic plaques, sometimes with a migratory nature. Erythrokeratoderma is often inherited as an autosomal dominant trait caused by mutations in the genesGJB3,GJB4orGJA1, encoding connexins 31, 303, and 43, respectively. Ery-throkeratoderma may be associated with neurological anomalies and can be caused by mutations inELOVL4. Recently,mutations inKDSR(3-ketodihydrosphingosine reductase), encoding an enzyme in the ceramide pathway, were also demonstrated to lead to erythrokeratoderma. Erythrokeratoderma should be distinguished from other skindiseases with erythematous and hyperkeratotic lesions in localized and well-demarcated patterns, such as KID (keratitis–ichthyosis–deafness) syndrome, MEDNIK syndrome, psoriasis,pityriasis rubra pilaris and some localized forms of keratinopathicichthyosis. Erythrokeratoderma should also not be confused with hereditary palmoplantar keratodermas (PPKs), especially when the lesions spread to adjacent areas. Loricrin keratoderma, causedby mutations inLOR, is another important differential diagnosis,the most distinctive but inconstant feature of which is the presence of a honeycomb PPK with digital constrictions.