About 120 million people worldwide suffer from congenital (early-onset) hearing loss. Thirty percent of them have syndromic hearing loss and the remaining 70% have non-syndromic hearing loss. In addition, a large number of elderly people worldwide suffer from age-related (late-onset) hearing loss. c-Ret and c-RET have been shown to be essential for the development and maintenance of neurons inc...

Mutation of the GJB2 gene, which encodes the connexin 26 (Cx26) gap junction (GJ) protein, is the most common cause of hereditary, sensorineural hearing loss. Cx26 is not expressed in hair cells, but is widely expressed throughout the non-sensory epithelial cells of the cochlea. Most GJB2 mutations produce non-syndromic deafness, but a subset produces syndromic deafness in which profound hearin...

Over the last decade, a number of distinct mutations in the mtDNA (mitochondrial DNA) have been found to be associated with both syndromic and non-syndromic forms of hearing impairment. Their real incidence as a cause of deafness is poorly understood and generally underestimated. Among the known mtDNA mutations, the A1555G mutation in the 12S gene has been identified to be one of the most commo...

It is estimated that hereditary hearing loss accounts for 60% of deafness in the developed countries. About 30% of hereditary hearing impairment is syndromic which involves other presenting abnormalities along with deafness. There are more than 400 syndromes which include various degrees of hearing impairment with different phenotypes. (Barlow Stewart et al., 2007; Berrettini et al., 2008). Abn...

BACKGROUND Deafness is the most common sensory disability in the world. Globally, mutations in GJB2 (connexin 26) have been shown to play a major role in non-syndromic deafness. Two other connexin genes, GJB6 (connexin 30) and GJA1 (connexin 43), have been implicated in hearing loss, but these genes have seldom been investigated in black Africans. We aimed to validate the utility of testing for...

Childhood deafness is quite bothersome and a common problem. EBM documents that serious hearing impairment is found in one in 800 newborns. Amongst the 50 percent of permanent childhood deafness, 30 percent is syndromic and is thought to be because of abnormal genetic makeup. Syndromic cases of deafness are more accurately diagnosed by the associated additional features of the syndrome. Waarden...

Mutations in the connexin26 (Cx26) gene are not only a major cause of nonsyndromic deafness, but can also cause syndromic forms of hearing loss that are associated with palmoplantar keratoderma (PPK, i.e., Vohwinkel's syndrome). It is not clear how two very distinct pathologies can arise from different mutations within the same connexin gene. This review summarizes the available data on wildtyp...

Mutations in the GJB2 gene are the most common cause of sensorineural non-syndromic deafness in different populations. One specific mutation, 35delG, has accounted for the majority of the mutations detected in the GJB2 gene in many countries. The aim of this study was to determine the prevalence of GJB2 mutations and the del(GJB6-D13S1830) mutation in non-syndromic deaf Brazilians. The 33 unrel...

BACKGROUND More than 70 % of the cases of congenital deafness are of genetic origin, of which approximately 80 % are non-syndromic and show autosomal recessive transmission (DFNB forms). To date, 60 DFNB genes have been identified, most of which cause congenital, severe to profound deafness, whereas a few cause delayed progressive deafness in childhood. We report the study of two Algerian sibli...