GJB2 (Connexin 26) Sequencing for GJB2-Related Ectodermal Dysplasia Test Details
Several syndromes characterized by ectodermal dysplasia and hearing loss are associated with variants in the GJB2 gene including KID syndrome, Vohwinkel syndrome, Bart-Pumphrey syndrome. Overlapping clinical features between these syndromes include hearing loss, palmoplantar keratoderma, and ichthyosis. Other features which may be specific to a particular syndrome include: keratitis, knuckle pads, leukonychia or nail dystrophy, and alopecia. GJB2 related ectodermal dysplasias are inherited in an autosomal dominant manner where as recessive variants in this gene are associated with isolated hearing loss.
|GJB2||Gap Junction Protein, Beta-2||121011||13q11-q12|
Sequencing of the GJB2 gene would be recommended for individuals with a suspected diagnosis of any of the GJB2-related ectodermal dysplasias or for individuals with hearing loss, a dominant family history, and palmoplantar keratoderma and ichthyosis.
This test is performed by Sanger sequencing of the coding regions and splice sites of the GJB2 gene. This test does not detect large deletions or variants in non-coding regions that could affect gene expression.
Analytical and Clinical Sensitivity
This test is greater than 99.9% accurate in detecting variants in the sequence analyzed. The clinical sensitivity for each of the associated conditions may vary and the overall detection rate is unknown.