To the Editor This letter corrects our diagnosis from 1986, documents the CAST mutation in our patients from that time, and adds to the list of genodermatoses that may mimic pachyonychia congenita (PC).
The gold standard for diagnosis of genetic skin diseases is the demonstration of the causative gene mutation. The dominantly inherited genodermatosis PC is caused by a mutation in K6a, K6b, K6c, K16, or K17.1 Pachyonychia congenita can be clinically misdiagnosed, with reports of Clouston syndrome mimicking PC, and the correct diagnosis can only be made by gene mutational analysis.2
Haber RM, Rose TH. Identification of a CAST Mutation in a Cohort Previously Misdiagnosed as Having Autosomal Recessive Pachyonychia Congenita. JAMA Dermatol. 2015;151(12):1393-1394. doi:10.1001/jamadermatol.2015.2810