Late postnatal onset of hearing loss due to GJB2 mutations.

GJB2 mutations account for approximately 50% of recessive non-syndromic deafness, with 35delG being the most prevalent. Homozygous 35delG mutations cause pre-lingual, non-progressive hearing loss that is detected on newborn hearing screening programmes. We present a sibling pair with homozygous 35delG mutations, who passed hearing tests in early infancy and developed progressive sensorineural hearing loss, one requiring a cochlear implant. These cases illustrate that deafness due to such mutations may have a late onset and consequently be missed on neonatal screening programmes and they may present an argument to consider neonatal screening for GJB2 mutations in order to aid early intervention.