GJB2 and autosomal recessive nonsyndromic hearing loss 1A: The most common non-syndromic deafness (DFNB1A) has been linked to more than 300 mutations in GJB2 (see http://deafnessvariationdatabase.org/letter/g, then select “GJB2′′); these mutations can be missense, non-sense, frameshift, insertions, and deletions; of which non-sense/truncating mutations, such as 35delG, are the prevalent forms in some populations (Mammano, 2018).