Phenotypes of two Dutch DFNA3 families with mutations in GJB2

Abstract

OBJECTIVES: We describe the phenotype of 2 Dutch DFNA3 families with mutations in the GJB2 gene. METHODS: Two patients from family 1 and one isolated patient from family 2 were studied. The audiometric examination consisted of pure tone and speech audiometry. Two patients underwent vestibular testing and high-resolution computed tomographic scanning of the temporal bone. Mutation analysis of GJB2 and GJB6 was performed. RESULTS: All 3 patients had severe to profound sensorineural hearing impairment. Cochlear implantation was performed in 2 patients, and their phoneme recognition scores were good. Mutation analyses revealed a p.Arg184Gln mutation in GJB2 in family 1 and a p.Arg75Trp mutation in GJB2 in family 2. No mutations in GJB6 were identified. Vestibular function tests and computed tomographic scans yielded normal findings in the examined subjects. CONCLUSIONS: Severe to profound sensorineural hearing impairment was found in these DFNA3 patients, and was well rehabilitated with cochlear implantation. A thorough genotype-phenotype correlation is difficult because of the small number of affected patients and the limited clinical data of these patients. More clinical data on DFNA3 families need to be published in order to create a reliable and precise phenotype characterization.