NIH
Zebra of the Week: Pachyonychia congenita
Pachyonychia congenita (PC) is a rare, inherited disorder primarily affecting the nails and skin that's characterized by thickened, abnormally shaped fingernails and toenails, painful calluses, and blisters on the soles of the feet and, less frequently, on the palms of the hands. Additional features may include leukokeratosis, follicular hyperkeratosis, and various types of cysts, including steatocystoma. PC is caused by mutations in specific keratin genes and is divided into five types based on the affected gene: PC-K6a, PC-K6b, PC-K6c, PC-K16, and PC-K17. All forms are inherited in an autosomal dominant manner. Symptoms of PC typically begin at birth or early childhood. There's currently no cure for PC, with treatments focusing on symptom management.
Source:
NIH GARD. (Accessed 2025, April 7). Pachyonychia congenita. https://rarediseases.info.nih.gov/diseases/10753/pachyonychia-congenita