Pachyonychia Congenita: New Classification and Diagnosis

We would like to emphasize the importance of genetic testing to confirm a clinical diagnosis, draw your attention to the revised classification of pachyonychia congenita (PC) and provide further information regarding this rare skin disorder. Historically, PC was subdivided, with the two major clinical forms being PC-1 and PC-2. With an improvement in the understanding of the disease based on detailed clinical and molecular data collected by the International PC Research Registry (IPCRR), a new classification system was proposed, that divides PC into five subtypes based on the keratin gene affected.[2] The authors referred to this publication, but they did not mention the new classification, which is more scientific and has mutational analysis as the discriminator. Reference of the disease as PC-1 and PC-2 is obsolete and should be revised in the published literature. Analysis of the IPCRR dataset showed considerable phenotypic overlap between cases classified as PC-1 and PC-2.[3]