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  1. Alessandro Terrinoni,
  2. Gerry Melino,
  3. Valeria Serra,
  4. Marco Alessandrini,
  5. Bianca Napolitano,
  6. Ernesto Bruno

Published Online: 15 SEP 2009

DOI: 10.1002/9780470015902.a0001453.pub2



How to Cite

Terrinoni, A., Melino, G., Serra, V., Alessandrini, M., Napolitano, B. and Bruno, E. 2009. Deafness. eLS. .

Author Information

  1. University of Rome “Tor Vergata”, Via Montpellier, Rome, Italy

Publication History

  1. Published Online: 15 SEP 2009


Recent statistical data indicate that in western countries, at least 1:1000 suffer of congenital hearing impairment. Genetic factors are responsible for more than 60% of the congenital cases. Sometimes, however, hearing loss is a multifactorial disorder caused by both genetic and environmental factors. Molecular genetics of deafness has experienced remarkable progress in the last decade. Genes responsible for hereditary hearing impairment are being mapped and cloned progressively. This article, while reporting some syndromic conditions related to deafness, focuses on nonsyndromic hearing loss. Genes involved in this type of pathologic condition have only recently begun to be identified. Owing to genetic heterogeneity, private nature of most mutations and large size of most deafness genes, the molecular diagnostic possibilities in recessive deafness are today limited only for a few genes. Facility and benefits of genetic tracking, in particular, should make it an important public health issue so that determinations of early diagnosis of hearing loss can be properly established.

Key concepts:

  • Deafness is the most common sensory deficit in humans, affecting 1 in 1000 new-born, and to date more than 23 different DFNB proteins have been discovered.

  • DFNB proteins can be classified into two classes: (1) genes regulating potassium homeostasis and (2) genes producing proteins that are important in the formation of stereocilia.

  • Owing to genetic heterogeneity, the molecular diagnostic possibilities in recessive deafness are still limited. However, facility and benefits of genetic tracking should make them an important public health issue.


  • hereditary hearing loss;
  • myosin;
  • connexin 26;
  • ear;
  • sensory hair cells;
  • organ of Corti