Bilateral congenital corneal anesthesia in a patient with SCN9A mutation, confirmed primary erythromelalgia, and paroxysmal extreme pain disorder.
Kim DT, Rossignol E, Najem K, Ospina LH
Journal of AAPOS : the official publication of the American Association for Pediatric Ophthalmology and Strabismus •
The SCN9A gene codes for the sodium voltage-gated channel NaV 1.7. Gain of function mutations cause pain disorders such as primary erythromelalgia, paroxysmal extreme pain disorder, and small fiber neuropathy. Loss of function mutations lead to congenital insensitivity to pain. We report the case of a 6-year-old girl with a SCN9A mutation who presented with both gain of function and loss of function phenotypes, including congenital corneal anesthesia.