Connexin-26 Gene Testing
Test Information/Clinical Significance
Although a number of genes play a role in deafness, mutations in the Connexin-26 gene are significantly increased in persons with deafness. These mutations are important in a large percentage (50%) of patients with autosomal, non-syndromic congenital deafness as well as in sporadic deafness (10-30%).
This testing is mainly useful for the investigation of young children with non-syndromic congenital deafness in whom recessive (two copies) inheritance of Connexin-26 mutations may cause deafness. Some persons may be carriers of one Connexin-26 gene mutation, however some carriers may have deafness as a consequence of other, non-Connexin-26 gene mutations.
Testing may also be useful for the assessment of older persons with hearing loss.
Method
The testing performed in the Sonic Clinical Institute involves amplification by PCR of exon 2 of the GJB2 gene followed by bi-directional sequencing.
Genetic Counselling
Genetic counselling is an essential aspect of testing for all genetic disorders and should be offered to patients prior to referral for testing and for discussion of test results.
Specimen
5 mL EDTA (dedicated tube required)
Results Availability
Test performed weekly