Punctate palmoplantar keratoderma type I, also called keratosis punctate palmoplantaris type Buschke-Fisher-Brauer, is a rare autosomal dominant hereditary skin disease characterized by multiple hyperkeratotic centrally indented papules that develop in early adolescence or later and are irregularly distributed on the palms and soles. In mechanically irritated areas, confluent plaques can be found. Interfamilial and intrafamilial severity shows broad variation. There have been reports of an association between PPKP and the development of early- and late-onset malignancies, including squamous cell carcinoma (summary by Giehl et al., 2012).
Another form of PPKP type I has been mapped to chromosome 8q24 (PPKP1B; 614936).
Other forms of punctate palmoplantar keratoderma include a porokeratotic type (PPKP2; 175860) and focal acrohyperkeratosis (PPKP3; 101850).
For a general phenotypic description and a discussion of genetic heterogeneity of palmoplantar keratoderma (PPK), see epidermolytic PPK (144200). [from
OMIM]