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Hereditary sensorineural hearing loss of unknown cause involving mitochondrial DNA 1555 mutation
S Iwasaki1, Y Tamagawa, S Ocho
1Department of Otolaryngology, Hamamatsu University School of Medicine, Hamamatsu, Japan. iwasaki@hama-med.ac.jp
Abstract:
We report on a family with maternally inherited sensorineural hearing loss, in which no history of aminoglycoside injection and no other specific etiology could be identified in any member. A 1555 A-to-G mutation of mitochondrial DNA was found in all members demonstrating hearing loss. The hearing in the propositus and his sister was severely impaired at a younger age than that in the mother. This case suggests that the 1555 point mutation of mitochondrial DNA has potential to promote inherited nonsyndromic hearing loss without any known etiology.
Insights
Maternally inherited hearing loss in a family was linked to a mitochondrial DNA 1555 A-to-G mutation. This genetic factor may cause inherited nonsyndromic hearing loss even without known causes.
Area of Science:
- Genetics
- Otolaryngology
- Mitochondrial Biology
Background:
- Sensorineural hearing loss (SNHL) can be inherited maternally.
- Identifying the genetic basis of non-syndromic SNHL is crucial for diagnosis and counseling.
- Mitochondrial DNA mutations are implicated in various inherited disorders, including hearing loss.
Observation:
- A family presented with maternally inherited SNHL.
- No history of aminoglycoside exposure or other known etiologies for hearing loss was identified.
- All affected family members carried the 1555 A-to-G mutation in their mitochondrial DNA.
Findings:
- The 1555 A-to-G mutation in mitochondrial DNA was consistently found in all affected individuals.
- Affected siblings showed earlier onset and more severe hearing impairment compared to their mother.
- This mutation appears to be a significant genetic factor in this family's hearing loss.
Implications:
- The mitochondrial DNA 1555 A-to-G mutation is a potential cause of inherited nonsyndromic SNHL.
- This finding expands the known genetic spectrum of hearing loss.
- Genetic screening for the 1555 A-to-G mutation may be beneficial for families with unexplained SNHL.