Audiological Phenotypes of Connexin Gene Mutation Patterns: A Glance at Different GJB2/GJB6 Gene Mutation Profiles
Leonardo Franz,
Alessandro Incognito,
Chiara Gallo,
Licia Turolla,
Elisa Scquizzato,
Roberta Cenedese,
Alessandro Matarazzo,
Daniel Savegnago,
Paolo Zanatta,
Elisabetta Genovese,
Cosimo de Filippis,
Gino Marioni
Affiliations
Leonardo Franz
Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy
Alessandro Incognito
Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy
Chiara Gallo
Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy
Licia Turolla
Medical Genetics Unit, Treviso Hospital, 31100 Treviso, Italy
Elisa Scquizzato
Molecular Pathology Laboratory, Unit of Pathological Anatomy, Treviso Hospital, 31100 Treviso, Italy
Roberta Cenedese
Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy
Alessandro Matarazzo
Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy
Daniel Savegnago
Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy
Paolo Zanatta
Department of Anesthesiology and Critical Care, Treviso Hospital, 31100 Treviso, Italy
Elisabetta Genovese
Otorhinolaryngology Unit, Department of Medical and Surgical Sciences for Children and Adults, University of Modena and Reggio Emilia, 41121 Modena, Italy
Cosimo de Filippis
Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy
Gino Marioni
Phoniatrics and Audiology Unit, Department of Neuroscience DNS, University of Padova, 35122 Treviso, Italy
GJB2 mutations are the most common cause of autosomal-recessive non-syndromic sensorineural hearing loss (SNHL). The available evidence shows large phenotypic variability across different genotypes and allelic variants. The aim of this study was to investigate the clinical and audiological features of a cohort of subjects with different GJB2/GJB6 gene mutation profiles from a tertiary referral center in Northeastern Italy. We considered 57 patients with GJB2/GJB6 mutations presenting with congenital, non-syndromic SNHL, mainly coming from the Veneto region (Italy). The samples were screened for mutations in exons 1 and 2 of the GJB2 gene and for the GJB6 gene deletion del (GJB6-D13S1830). Free-field and air-conduction frequency-specific thresholds and the pure-tone average (PTA) were considered in the statistical analysis. Five patients (8.87%) had connexin gene mutations in simple heterozygosis, 15 (26.31%) in compound heterozygosis, 34 (59.64%) in homozygosis, and 3 (5.26%) with digenic patterns. The frequency-specific air-conduction thresholds showed significantly different mean values across the different genotypes (Roy’s largest-root test, p = 0.0473). Despite the evidence already available on genetic SNHL, many new insights are to be expected. Further large-scale prospective studies including different populations are necessary to confirm these preliminary findings about the clinical and audiological features of patients with different GJB2/GJB6 gene mutation patterns.
