1. Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
2. Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, Illinois2Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
3. Pachyonychia Congenita Project, Salt Lake City, Utah
4. Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois