Predictive Value of GJB2 Mutation Status for Hearing Outcomes of Pediatric Cochlear Implantation

Abstract

Objective To systematically review and quantify current evidence regarding the association of GJB2 mutation status with outcomes of pediatric cochlear implantation. Data Sources PubMed, Embase, and the Cochrane Library were searched for "GJB2,""pediatric hearing loss," and "cochlear implantation" and their synonyms, with no language restrictions, until December 2, 2015. Review Methods Studies were included that investigated the status of GJB2 mutation and its predictive value for outcomes of pediatric cochlear implantation. Speech recognition scores, Infant-Toddler Meaningful Auditory Integration Scale, Speech Intelligibility Rating, and Categorized Auditory Performance were pooled using weighted mean differences, and a 95% confidence interval. Results Eighteen studies met the inclusion criteria. The differences between GJB2-related deafness and non- GJB2-related deafness due to unidentified causes and other types of genetic deafness without additional disabilities were not statistically significant ( P = .15 and P = .30, respectively); however, the difference between GJB2-related deafness and acquired hearing loss due to environmental etiologies was statistically significant and favored GJB2-related deafness ( P = .03). Conclusion GJB2-related deafness leads to significantly better cochlear implantation outcomes when compared with acquired deafness caused by environmental etiologies. However, GJB2 mutation is not associated with a significantly better prognosis when compared with those whose deafness results from either nonsyndromic hearing loss of unknown origin or other types of genetic mutations in the absence of other neurologic deficits.

Cochlear Implantation Outcome in Children with DFNB1 locus Pathogenic Variants

“…Previously published data were based on the analysis of a limited number of patients wherein the most numerous group was almost four times smaller than ours (40 vs. 149) [8,31]. Moreover, there was a large variation in the time of implantation, ranging from 1 to even 14 years of age [8,32]. The patients described in a single study have often been exposed to different environmental factors, such as different lengths of auditory deprivation, as well as having different levels of natural ability to acquire auditory skills [3].…”

“…All patients were treated in one medical center. Previously published data were based on the analysis of a limited number of patients wherein the most numerous group was almost four times smaller than ours (40 vs. 149) [8,31]. Moreover, there was a large variation in the time of implantation, ranging from 1 to even 14 years of age [8,32].…”

“…Some cochlear implant users have little or no benefit from using them, and as many as 7% of children stop using cochlear implants [6,7]. The development of auditory competence of cochlear implant users is influenced by many factors, including the etiology of HL, the level of residual hearing preservation, the coexistence of other medical problems, as well as the length of auditory deprivation and the intensity of speech and hearing rehabilitation [8].…”

Cochlear Implantation From the Perspective of Genetic Background

“…For patients with severe phenotypes who possess GJB2 mutations, genetic information would aid in decision making regarding CI, as their hearing loss is of cochlear origin and they, therefore, would be good candidates for CI. The present literature review indicates that the majority of papers showed significant improvement in speech performance in GJB2 ‐related deafness patients and the remaining papers showed equivalent results between GJB2‐ related deafness and non‐ GJB2 deafness (for review; Abdurehim et al, ; Nishio and Usami, ). The difference in these results is probably due to patient selection bias.…”

Hearing Loss Etiology in Patients Submitted to Cochlear Implant

“…It is estimated that nearly 50% of pre-lingual deafness cases have a genetic connection. 1,10 In 70% of those cases, it is related to a non-syndromic mutation, 80% being of recessive inheritance, 15% of dominant inheritance and 1% linked to the X cromossome. 7 The most common mutation occurs in the GJB2 gene, responsible for coding the connexin 26.…”