GJB2 35delG — non-syndromic hearing loss carrier
A GJB2 35delG variant has been detected.
You have at least one copy of the GJB2 35delG gene change, the most common genetic cause of inherited hearing loss.
One copy means carrier status — usually no hearing impact. Two copies are consistent with congenital sensorineural hearing loss (DFNB1), the most common single genetic cause of hearing loss. If you have not been diagnosed and the result is unexpected, clinical confirmation is appropriate.
With one copy, you're a carrier — your hearing is almost certainly unaffected. With two copies, this is consistent with the most common genetic cause of inherited hearing loss, which is typically present from birth. If you don't already know you have hearing loss and the result is surprising, get a clinical lab to confirm.
What this means
GJB2 encodes connexin 26, a protein that forms gap junctions in the cochlea. The 35delG variant is the most common cause of autosomal recessive non-syndromic hearing loss in many populations, particularly European-descent populations. The hearing loss is typically congenital or early-onset, bilateral, and sensorineural. Carrier (heterozygous) status is common (~3% of European-descent individuals) and benign.
GJB2 makes a protein called connexin 26, which forms tiny channels between cells in the inner ear that let the hearing machinery work. The 35delG change breaks this protein and is the most common single genetic cause of inherited hearing loss in many populations, particularly people of European descent. When it causes hearing loss, it typically affects both ears, is present from birth or appears very early, and is the "sensorineural" type (originating in the inner ear). About 3% of people of European descent carry one copy with no effect on their own hearing — it only causes hearing loss when both copies are affected.
Caveats
- Carriers are typically unaffected; this matters mainly for family planning.
- Two-copy results without a known hearing loss diagnosis warrant clinical evaluation.
- There are many other genes that cause hearing loss; GJB2 is the largest single contributor in some populations.