Identification of a recurrent mutation in keratin 6a in a patient with overlapping clinical features of pachyonychia congenita types 1 and 2.

Pachyonychia congenita is characterized by hypertrophic nail dystrophy and associated ectodermal features. PC-1 subtype is associated with mutations in keratins 6a or 16, whereas PC-2 subtype is linked to mutations in keratins 6b or 17. The correlation between the mutated gene and the type of PC has generally been consistent. In this report, we describe a case with overlapping clinical features of PC-1 and PC-2 in which a mutation in K6a was identified.