Pachyonychia congenita (PC) is a rare genodermatosis of autosomal dominant pattern of inheritance, affecting nails, skin, oral mucosa, larynx, hair and teeth. The clinical phenotype is a result of a pathogenic mutation in one of the genes encoding keratins. Owing to recent clinical and molecular analyses of patients from the International Pachyonychia Congenita Research Registry it was possible to start clinical trial on gene therapy using small interfering RNA molecules to knock out the mutant keratin. This novel approach is opening up a new avenue for the treatment of genetic skin diseases. We report a case of a 9-year-old girl with pachyonychia congenita type 1 (PC-1), previously termed Jadassohn-Lewandowsky syndrome, suffering from the most frequent of the known mutations – KRT6aN172del.