Bilateral Simultaneous Cochlear Implantation in Monozygotic Twins with Congenital Hearing Loss due to a GJB2 Compound Heterozygous Pathogenic Variant

Abstract

We encountered a case of monozygotic twin girls with identical GJB2 compound heterozygous mutations who underwent simultaneous bilateral cochlear implantation at the same age. The first- and second-born twins were both referred for further evaluation after their newborn hearing screenings indicated bilateral hearing loss. They were subsequently diagnosed with severe hearing loss through ASSR testing. Bilateral hearing aids were fitted at six months of age. Genetic testing for hearing loss confirmed GJB2 compound heterozygous mutations, leading to simultaneous bilateral cochlear implantation at 17 months of age. The preoperative thresholds with hearing aids and postoperative hearing ability differed between the twins up to 15 months postoperatively; however, assessments at 2.5 years postoperatively using IT-MAIS and LittleEARS showed equivalent auditory capabilities. Bilateral cochlear implantation at the same age in twins with congenital hearing loss and identical genetic mutations appears to be beneficial for speech and language development.