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Genetic analysis for a specific mutation in the *GJB2* gene (connexin 26)

Published: August 9, 2026Updated: August 16, 2026

This test checks for a known mutation in the GJB2 gene, which is linked to certain hearing loss and skin conditions.

Quick summary

["Helps identify if the mutation is present that may cause genetic disorders."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
82138-9
Short code
GJB2 c.35delG Mut Anl Bld/T
Synonyms
GJB2 c.35delG Mut Anl Bld/T
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
molgen
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your doctor may recommend this test if you have a family history of hearing loss, skin disorders (like erythroderma), or other related genetic conditions. It’s also used in prenatal testing or genetic counseling for at-risk families.

What to Expect Before the Test

No special preparation is needed. A blood sample is typically taken from a vein in your arm. If testing is done during pregnancy, a blood sample or amniocentesis may be used.

What the Results Mean

Results will indicate whether the specific GJB2 mutation is present. A positive result means the mutation is detected, which can guide further medical management or genetic counseling.

Common Conditions Linked to This Mutation

The GJB2 mutation is strongly associated with **hereditary deafness** (congenital sensorineural hearing loss) and, in some cases, **keratitis-ichthyosis-deafness (KID) syndrome**, which includes skin abnormalities and eye inflammation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is critical for diagnosing genetic disorders early, enabling targeted interventions (e.g., hearing aids, genetic counseling) and supporting family planning decisions. Early detection can also help manage symptoms and reduce complications associated with the condition.

Short name

GJB2 Gene Mutation Test

Frequently asked questions

What does a positive result mean?
A positive result means the specific GJB2 mutation is confirmed in your DNA. This finding may explain your or your child’s symptoms and guide further medical or genetic care.
Will this test affect my insurance or treatment options?
Results from this test are confidential and used to inform medical decisions. Insurance coverage depends on clinical necessity; your doctor will discuss coverage details with you.
Can this test be done during pregnancy?
Yes, prenatal testing for GJB2 mutations is available through blood tests or amniocentesis. Your healthcare provider will determine the best approach based on your risk factors.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy