New mutations of Darier disease in Tunisian patients

Darier's disease (DD, MIM 124200) also known as Darier-White disease and keratosis follicularis, is a rare autosomal dominant skin disorder characterized by warty papules and plaques in the seborrheic area (central trunk, flexures, scalp, and forehead). Pathogenic mutations in the ATP2A2 gene encoding the sarcoplasmic/endoplasmic reticulum Ca(2+) ATPase (SERCA) 2 gene underlie the disease. In the present study, we performed genetic investigation of three unrelated Tunisian families affected by DD. Mutation screening was performed by direct sequencing of the coding region and exon/intron boundaries of the ATP2A2 gene. Patients in the 3 studied families exhibited classical DD phenotype. DD was associated with neurological and cardiac disorders in one family. Two novel mutations were identified: a missense mutation (R559Q) and a frameshift mutation (1713-1714 del 2A). Both pathogenic mutations are located in exon 13 of the ATP2A2 gene and affected the ATP-binding site of the SERCA2 protein. In one family, no mutation was found within the coding region and exon/intron boundaries of the ATP2A2 gene. Our findings provide further evidence for the genetic heterogeneity of DD in Tunisia and that most mutations involved in this disease are family specific.