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Phenotype/genotype correlations in a DFNB1 cohort with ethnical diversity
1Department of Otolaryngology, University of Miami Ear Institute, University of Miami Miller School of Medicine, Miami, Florida 33136, USA. sangeli@med.miami.edu
The Laryngoscope
|September 2, 2008
Summary
DFNB1 is a common cause of prelingual deafness in children. Genetic screening for DFNB1, particularly in diverse populations, is crucial for accurate diagnosis and genetic counseling.
Area of Science:
- Genetics
- Audiology
- Pediatrics
Background:
- Nonsyndromic sensorineural hearing loss (HL) is a significant cause of childhood disability.
- DFNB1, associated with GJB2 and GJB6 genes, is a primary genetic cause of prelingual deafness.
Purpose of the Study:
- To determine the prevalence of DFNB1 in children with prelingual nonsyndromic HL.
- To investigate genotype-phenotype correlations in affected children.
- To develop guidelines for genetic counseling regarding DFNB1.
Main Methods:
- Prospective cohort study of 119 unrelated children with prelingual nonsyndromic HL.
- Mutational screening of GJB2 (coding and noncoding exons) and GJB6 (del(GJB6-D13S1830) mutation).
- Collection of demographic, audiological, developmental, and phenotypic data.
Main Results:
- DFNB1 prevalence was 26% in the cohort, higher in familial (50%) than sporadic (25%) cases.
- Hispanics of mixed descent showed greater allelic heterogeneity in GJB2 variants.
- Hearing phenotype varied, with no clear genotype-class correlation; inner ear abnormalities were infrequent (8%).
Conclusions:
- DFNB1 is the most common identifiable cause of prelingual deafness in this ethnically diverse cohort.
- Extended genetic screening, including noncoding regions and the DFNB1 locus, is recommended, especially for Hispanics.
- Audiometric profile alone is insufficient for DFNB1 screening due to phenotypic variability; genetic counseling is essential.
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