A non-syndromic hearing loss (DFNB1) is a congenital and autosomal recessive disease. It can also be defined as a non-progressive sensorineural hearing loss ranging from moderate to severe. As 98% of patients have mutations in Connexin gene 26 (GJB2), 2% of them have mutations at Connexin 30 (GJB6) gene region.

Some detected mutations in GJB2 gene which are autosomal dominant, lead to nonsyndromic hearing loss (DNA3) . GJB2 gene locus is on the long arm of chromosome 13 and encodes a 226 amino acid long protein.