The incidence of congenital, prelingual hearing loss is approximately one in 1000 births. Approximately 70% of prelingual genetic hearing loss is nonsyndromic (i.e. not associated with visible abnormalities of the external ear or related medical findings). Pathogenic variants in the GJB2 gene, which encodes the protein Connexin 26, are responsible for the most common form of non-syndromic sensorineural deafness type 1 (DFNB1).
DFNB1 is an autosomal recessive form of sensorineural hearing loss which results from damage to the neural receptors of the inner ear, the nerve pathways to the brain, or the area of the brain that receives sound information. Approximately 98% of affected individuals are homozygous or compound heterozygous for pathogenic variants in the GJB2 gene.
In a further 2% of DFNB1 patients, heterozygosity for a GJB2 mutation and a 342-kb deletion affecting part of the GJB6 gene (encoding the Connexin 30 protein) is observed. A variant involving the splicing site of the non-coding exon 1 of GJB2 is an infrequently reported variant.
Note that analysis of the SLC26A4 gene implicated in Pendred syndrome is also available as a seperate test (see Test Manager).
Genetics - Molecular Pathology
MOLP
Connexin 26 Gene Analysis
DFNB1 sequencing
GJB2 sequencing
GJB6 sequencing
4 weeks
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