Further evidence of the clinical and genetic heterogeneity of recessive transgressive PPK in the Mediterranean region.

Transgressive palmoplantar keratoderma (PPK) is the phenotypic hallmark of Mal de Meleda (MDM, MIM 24300). It is characterized by erythema and hyperkeratosis that extend to the dorsal face of the hands and feet. The disease is distributed worldwide and includes the Mediterranean population. The gene responsible for MDM, ARS (component B) mapped on chromosome 8qter, encodes for the SLURP-1 protein (Ly-6/uPAR related protein-1). A variety of mutations within the ARS gene have been shown to underlie MDM in different populations. Genetic heterogeneity of MDM is suspected. We have recently shown that three different homozygous mutations (82delT, C77R, C99Y) were responsible for MDM in 17 patients from Northern Tunisia belonging to eight unrelated consanguineous families. We report here a Tunisian family with three siblings presenting with recessive transgressive PPK closely resembling the MDM phenotype that excludes linkage to the ARS gene.