Version July 2025
| Type of PPK | Mode of inheritance | Responsible gene | Characteristic clinical manifestation |
| Focal | |||
| Focal PPK | AD | KRT16, KRT6c, DSG1, TRPV3 | Circumscribed calluses on the palms and soles with slight or no nail lesions. The lesion can be painful and induced by mechanical stress. |
| Striate | |||
| Striate PPK 1 | AD | DSG1 | Skin thickening is prominent in a linear pattern along the flexor aspects of the fingers and over pressure points on the soles. Types I to III are classified by the responsible gene. |
| Striate PPK 2 | AD | DSP | |
| Striate PPK 3 | AD | KRT1 | |
| Punctate | |||
| Punctate PPK type 1A (Buschke-Fischer-Brauer type) | AD | AAGAB | Multiple tiny, punctate keratosis on the palms and soles appear during late childhood to adolescence and increase in number with age to form larger lesions. Type 1A and 1B are classified by the responsible genes. |
| Punctate PPK type 1B | AD | COL14A1 | |
| Punctate PPK type 2 (porokeratotic type) | AD | Unknown | Tiny, keratotic spines on the palms and soles begin during the early 20s. Histologic examination reveals columnar parakeratosis. |
| Punctate PPK type 3 (acrokeratoelastoidosis) | AD | Unknown | Small, keratotic papules that mainly involve the margins of the hands and feet appear in adolescence or adult life. Histologic examination reveals degeneration of elastic fibers. |
