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GJB2 mutations in the Swiss hearing impaired
Nicolas Gürtler1, Yuil Kim, Anand Mhatre
1Laboratory of Molecular Otology, Epstein Laboratories, Department of Otolaryngology-Head and Neck Surgery, University of California San Francisco, USA.
Ear and Hearing
|October 10, 2003
Summary
GJB2 gene mutations are a significant cause of early-onset hearing loss in Swiss children under two. Denaturing high-performance liquid chromatography (DHPLC) effectively screens for these connexin 26 (Cx26) mutations.
Area of Science:
- Genetics
- Audiology
- Molecular Biology
Background:
- Mutations in the GJB2 gene, encoding connexin 26 (Cx26), are a primary genetic cause of nonsyndromic hearing loss.
- The prevalence and spectrum of GJB2 mutations in the Swiss population with hearing impairment were previously undefined.
Purpose of the Study:
- To ascertain the frequency and types of GJB2 mutations in Swiss children diagnosed with hearing impairment before and after age two.
- To evaluate the diagnostic efficacy of denaturing high-performance liquid chromatography (DHPLC) for GJB2 mutation screening.
Main Methods:
- Mutation screening of the GJB2 gene's coding exon in 34 hearing-impaired patients.
- Utilized DHPLC for initial screening, followed by bidirectional sequencing for confirmation of sequence alterations.
Main Results:
- GJB2 mutations were identified in 45% of children under two years old, compared to 14% in those diagnosed at or after two years.
- The 313del14nt mutation was common in younger children, while the 35delG mutation was exclusively found in this age group.
- DHPLC demonstrated 100% sensitivity and 83% specificity for detecting GJB2 sequence variations.
Conclusions:
- GJB2 mutations are a leading genetic cause of nonsyndromic hearing impairment in young Swiss children.
- GJB2 mutations are less frequent in Swiss patients diagnosed with hearing loss after age two.
- DHPLC is a highly sensitive and effective method for GJB2 mutation detection in clinical diagnostics.