The c.35delG mutation in the GJB2 gene has been identified as the most important among genetic causes of hearing impairment as it accounts for the majority of mutations in deaf Caucasians, whether in the homozygous state or as one of the mutations in compound heterozygosity (within GJB2 or in GJB6 gene) [4,7]. The gene discussed is GJB2; the disease is Hearing impairment.