Pachyonychia Congenita: A Spectrum of KRT6a Mutations in Australian Patients.

Background: Pachyonychia congenita (PC) is a rare inherited disorder of keratinization characterised by hypertrophic nail dystrophy, painful palmoplantar blisters, cysts, follicular hyperkeratosis and oral leukokeratosis. It is associated with mutations in five differentiation-specific keratin genes, KRT6A, KRT6B, KRT6C, KRT16, or KRT17.

Objectives: Living with Pachyonychia Congenita can be isolating. The aim of this paper is to document a single patient's experience within a national context.

Method: We report the case of a 2 year old female with an atypical presentation of PC due to a mutation in KRT6A with severely hypertrophic follicular keratoses, skin fragility, relative sparing of nail hypertrophy on one hand and failure to thrive in early infancy. In collaboration with the International Pachyonychia Congenita Research Registry (IPCRR), a database search was performed using Australian residency and KRT6A mutation as inclusion criteria. The IPCRR database was also searched for a matching KRT6A mutation. Six Australian patients were identified in addition to one patient with an identical mutation residing in the United States. The detailed standardized patient questionnaire data was manually collated and analysed.

Results: Fingernail hypertrophy and oral leukokeratosis were the most common features. There was no recording of asymmetric distribution in any other Australian patient. Trouble nursing as an infant and follicular hyperkeratosis also occurred in the American patient, however they did not have asymmetric distribution and the oral leukokeratosis appeared later in life.

Conclusion: This case has unique features. Sharing information can assist patients navigating life with this condition.