Hearing loss is the most common birth defect, with estimates of 1:1000 children being born with profound or severe hearing loss. More than 70% of hereditary hearing loss cases are non-syndromic or isolated, that is, not in association with any other symptoms. In 85% of these non-syndromic cases, the deafness is transmitted as an autosomal recessive trait (DFNB type). As most autosomal recessive loci, DFNB22 causes prelingual severe-to-profound hearing loss.