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GTR Home > Conditions/Phenotypes > Hereditary hearing loss and deafness

Summary

Nonsyndromic hearing loss is a partial or total loss of hearing that is not associated with other signs and symptoms. In contrast, syndromic hearing loss occurs with signs and symptoms affecting other parts of the body.\n\nNonsyndromic hearing loss can be classified in several different ways. One common way is by the condition's pattern of inheritance: autosomal dominant (DFNA), autosomal recessive (DFNB), X-linked (DFNX), or mitochondrial (which does not have a special designation). Each of these types of hearing loss includes multiple subtypes. DFNA, DFNB, and DFNX subtypes are numbered in the order in which they were first described. For example, DFNA1 was the first type of autosomal dominant nonsyndromic hearing loss to be identified.\n\nThe characteristics of nonsyndromic hearing loss vary among the different types. Hearing loss can affect one ear (unilateral) or both ears (bilateral). Degrees of hearing loss range from mild (difficulty understanding soft speech) to profound (inability to hear even very loud noises). The term "deafness" is often used to describe severe-to-profound hearing loss. Hearing loss can be stable, or it may be progressive, becoming more severe as a person gets older. Particular types of nonsyndromic hearing loss show distinctive patterns of hearing loss. For example, the loss may be more pronounced at high, middle, or low tones.\n\nDepending on the type, nonsyndromic hearing loss can become apparent at any time from infancy to old age. Hearing loss that is present before a child learns to speak is classified as prelingual or congenital. Hearing loss that occurs after the development of speech is classified as postlingual.\n\nMost forms of nonsyndromic hearing loss are described as sensorineural, which means they are associated with a permanent loss of hearing caused by damage to structures in the inner ear. The inner ear processes sound and sends the information to the brain in the form of electrical nerve impulses. Less commonly, nonsyndromic hearing loss is described as conductive, meaning it results from changes in the middle ear. The middle ear contains three tiny bones that help transfer sound from the eardrum to the inner ear. Some forms of nonsyndromic hearing loss, particularly a type called DFNX2, involve changes in both the inner ear and the middle ear. This combination is called mixed hearing loss. [from MedlinePlus Genetics]

Available tests

19 tests are in the database for this condition.

Check Related conditions for additional relevant tests.

Genes See tests for all associated and related genes

  • Also known as: COI, MTCO1, COX1
    Summary: mitochondrially encoded cytochrome c oxidase I

  • Also known as: BRAIN-4, BRN-4, BRN4, DFN3, DFNX2, OCT-9, OTF-9, OTF9, POU3F4
    Summary: POU class 3 homeobox 4

  • Also known as: ARTS, CMTX5, DFN2, DFNX1, PPRibP, PRS-I, PRSI, PRPS1
    Summary: phosphoribosyl pyrophosphate synthetase 1

  • Also known as: MTRNR1, RNR1
    Summary: mitochondrially encoded 12S RNA

  • Also known as: Chisel, Csl, DFN6, DFNX4, MPD7, SMPX
    Summary: small muscle protein X-linked

  • Also known as: MTTS1, TRNS1
    Summary: mitochondrially encoded tRNA serine 1 (UCN)

Clinical resources

Practice guidelines

  • NICE, 2023
    UK NICE Guideline (NG98), Hearing loss in adults: assessment and management, 2023
  • NICE, 2019
    Cochlear implants for children and adults with severe to profound deafness (2019 Update)
  • ACMG ACT Sheet, 2018
    Newborn Screening ACT Sheet (Congenital Hearing Loss >30db)
  • ACMG ACT Sheet, 2010
    American College of Medical Genetics ACT SHEET, Congenital Hearing Loss, 2010
  • ACMG Algorithm, 2009
    American College of Medical Genetics Algorithm, Hearing Loss, 2009
  • NICE, 2009
    National Institute for Health and Clinical Excellence, Cochlear implants for children and adults with severe to profound deafness, 2009 [See 2019 Update, TA566]
  • ACMG Algorithm, 2009
    American College of Medical Genetics ACT SHEET, Newborn Screening ACT Sheet Algorithm, Congenital Hearing Loss, 2009

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