A novel dominant and a de novo mutation in the GJB2 gene (connexin-26) cause keratitis-ichthyosis-deafness syndrome: implication for cochlear implantation

Abstract

Objective: Keratitis-ichthyosis-deafness (KID) syndrome is a rare congenital disorder, characterized by hyperkeratosis and erythrokeratoderma associated with profound sensorineural hearing loss. Additional concomitant phenomena of the KID syndrome are dystrophic nails, dental abnormalities, scarring alopecia, and vascularizing keratitis. The disorder is caused by mutation in the GJB2 gene (connexin-26), a gap junction protein. The aim of this study was to explore the feasibility and procedure of cochlear implantation in patients with KID syndrome and to assess the genetic causes.

Study design: Retrospective case review.

Setting: Tertiary referral center. Cochlear implant program.

Patients: We report on 2 cases of KID syndrome with congenital profound hearing loss. A 50-year-old woman with skin necrosis and implant extrusion 5 years after cochlear implantation and a 10-month-old infant girl with bilateral deafness, alopecia, bright light sensitivity, and congenital dermatosis.

Intervention: Genetic analysis. Cochlear implantation.

Main outcome measures: Mutation analysis, surgical suitability, and hearing rehabilitation.

Results: We detected a novel heterozygous missense mutation (Ile30Asn) in Patient 1 and a de novo mutation (Asp50Asn) in the GJB2 gene (connexin-26) in Patient 2. To decrease the risk of skin flap necrosis, we describe alternative surgical cochlear implantation techniques with a novel very thin receiver/stimulator (Nucleus CI 513; Cochlear Corp.). The postoperative course of both patients has been without any problems until now.

Conclusion: The combination of the cutaneous lesions with visual and auditory impairment demands to diagnose impaired hearing as early as possible. It would be helpful to search for KID syndrome in dealing with patients with deafness, skin lesions of unknown cause, and wound healing problems to choose the right method of surgical treatment and subsequent aftercare.