Mutational analysis for GJB2, GJB6, and GJB3 genes in Campania within a universal neonatal hearing screening programme

AbstractObjective: To determine the incidence of GJB2 and GJB3 mutations and of two deletions upstream of the GJB6 gene in infants of the Campania region of southern Italy. Design: DNA samples from non-syndromic hearing-impaired infants enrolled in a neonatal screening programme for sensorineural hearing loss were analysed by PCR and by direct sequencing. The audiological features of infants with biallelic GJB2 mutations were also examined to identify genotype-phenotype correlations. Study sample: Molecular analyses were carried out in 129 affected and five unaffected infants. Results: A genetic etiology of hearing loss was identified in 28% of infants, including several at environmental risk of hearing loss. Neither GJB6 nor GJB3 (a gene not previously investigated in the Campania population) mutations were found. Conclusions: This study confirms the importance of universal neonatal hearing screening. The identification of a genetic cause in infants at environmental risk indicates that such infants shoul...