GJB2 (gap junction protein, beta 2, 26kDa, connexin 26) (eg, nonsyndromic hearing loss) gene analysis; known familial variants
CPT4 code
Name of the Procedure:
GJB2 Gene Analysis; Known Familial Variants (Gap Junction Protein, Beta 2, 26kDa, Connexin 26)
Summary
The GJB2 gene analysis is a genetic test used to identify known familial variants related to nonsyndromic hearing loss. By analyzing specific genetic mutations inherited within a family, this test can help assess the risk of hearing loss in family members.
Purpose
The procedure primarily addresses nonsyndromic hearing loss, which is hearing impairment not associated with other signs and symptoms. The goal is to confirm the presence of known familial variants of the GJB2 gene that cause hearing loss, enabling early intervention and management.
Indications
- Family history of nonsyndromic hearing loss
- Newborns or young children with unexplained hearing loss
- Adults with progressive hearing loss and a family history of the condition
- Individuals known to be carriers of a GJB2 gene mutation
Preparation
- No special preparation is usually required, but patients may be asked about their family medical history.
- A simple blood sample or a buccal swab (cheek swab) is typically collected for DNA analysis.
Procedure Description
- Sample Collection: A blood sample is drawn or a buccal swab is taken from the patient.
- DNA Extraction: DNA is extracted from the collected sample in a laboratory setting.
- Gene Sequencing: The GJB2 gene is sequenced to identify known familial variants associated with hearing loss.
- Data Analysis: Genetic sequencing data is analyzed and compared to known variants.
Tools, equipment, or technology used may include PCR machines and genetic sequencers. No anesthesia or sedation is required.
Duration
The sample collection itself takes only a few minutes, but the complete analysis typically takes a few weeks.
Setting
The sample collection can be performed in a doctor's office, clinic, or hospital. The genetic analysis is conducted in a specialized laboratory.
Personnel
- Primary care physician or genetic counselor (for initial consultation)
- Nurse or medical technician (for sample collection)
- Geneticist or laboratory technician (for DNA analysis)
Risks and Complications
- Minimal risk associated with blood draw (e.g., slight bruising or dizziness)
- Buccal swab is non-invasive and carries no risks
- Misinterpretation or inconclusive results if the family history is incomplete
Benefits
- Accurate diagnosis of genetic hearing loss
- Informed family planning and risk assessment
- Early intervention and management options for identified individuals
- Invaluable information for future family generations
Recovery
- No recovery time is necessary as the procedure is non-invasive.
- Patients can immediately resume normal activities.
Alternatives
- Whole Genome Sequencing: More comprehensive but also more expensive and time-consuming.
- Audiometric Tests: Non-genetic tests like audiograms to assess hearing loss.
- Other Genetic Tests: Analysis of different genes associated with hearing loss.
Pros and cons of alternatives vary, with some providing broader insights at higher costs and others focusing on symptomatic assessment without genetic information.
Patient Experience
- During the procedure: Minimal discomfort during blood draw or none with a buccal swab.
- After the procedure: No pain or recovery needed. Minor anxiety may be present while awaiting results. Pain management and comfort measures are generally unnecessary due to the non-invasive nature of the sample collection.