Pathogenic missense variants in the GJB2 gene, resulting in amino acid substitutions, lead to a variety of clinical outcomes, including the most common non-syndromic autosomal recessive deafness (DFNB1A), autosomal dominant deafness (DFNA3A), as well as syndromic forms combining hearing loss and skin disorders. This evidence concerns the gene GJB2 and autosomal recessive nonsyndromic hearing loss 1A.