Abstract: Objective To analyze the clinic features and hereditary characteristics of three subtypes of porokeratosis, namely disseminated superficial actinic porokeratosis (DSAP), porokeratosis palmaris et plantaris disseminata(PPPD) and porokeratosis of Mibelli (PM) in five pedigrees with porokeratosis. Methods After clinical and pathological diagnosis, every living family member of the five pedigrees with poro-kerotosis was undergoing medical examination and genetics analysis. These five pedigrees consisted of three DSAP pedigrees (totally 266 family members including 100 patients), and one PPPD pedigree (composing of 90 members including 26 patients), one PM pedigree (cornposing of 34 members including 17 patients). Results While diagnosed as porokeratosis, the five pedigrees included three distinctive variants, each with its own clinic characteristics. The lesions was initiated on the face in DSAP subtype, on palms and the flex-ion side of fingers in PPPD subtype; or involving sun-covered areas in PM subtype. Of the three subtypes of porokeratosis, the onset age in DSAP subtype was earliest, usually about 8-20 years old, about 14-20 years old in PPPD subtype, but PM subtype about 20-30 years old. Conclusions As a group of autosomal dominant genodermatosis, porokeratosis presented various clinic variants with different genetic basis. And, different subtype could be seen in a same patient or same pedigree.

Key words: Porokeratosis, Pedigree