A large mutational study in pachyonychia congenita

Area of Science:

• Genetics
• Dermatology
• Molecular Biology

Background:

• Pachyonychia congenita (PC) is a rare autosomal dominant skin disorder.
• Characterized by nail dystrophy, painful palmoplantar keratoderma, oral leukokeratosis, follicular keratosis, and cysts.
• PC is caused by heterozygous mutations in keratin genes KRT6A, KRT6B, KRT16, or KRT17.

Purpose of the Study:

• To identify mutations in keratin genes in 90 new families with Pachyonychia congenita.
• To expand the spectrum of known mutations associated with PC.
• To identify mutation hotspots for potential personalized medicine approaches.

Main Methods:

• Genetic analysis of 90 families diagnosed with Pachyonychia congenita.
• Sequencing of keratin genes KRT6A, KRT6B, KRT16, and KRT17.
• Analysis of mutation types, including missense, insertion/deletion, splice site, and nonsense mutations.

Main Results:

• Identified mutations in KRT6A, KRT6B, KRT16, or KRT17 in all 90 families, confirming clinical diagnoses.
• Discovered 21 previously unreported mutations and confirmed 22 known mutations.
• KRT6A mutations were most common (52%), followed by KRT16 (28%), KRT17 (17%), and KRT6B (3%).
• Most mutations were heterozygous missense or small in-frame insertion/deletion mutations within helix boundary motifs.

Conclusions:

• Genetic analysis confirms the causative role of KRT6A, KRT6B, KRT16, and KRT17 mutations in Pachyonychia congenita.
• The study expands the mutational landscape of PC and identifies mutation hotspots.
• Findings may facilitate the development of personalized medicine strategies for Pachyonychia congenita.