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 airconduction
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