SASH1 and palmoplantar keratoderma-sclerodactyly syndrome: Patients suffering from specific inherited forms of PPK (i.e. Huriez syndrome, Olmsted syndrome, a subset of patients suffering from keratitis-ichthyosis-deafness, hereditary dyschromatosis that is due to mutations in SASH1 gene) are prone to SCC development [16, 17, 48].