CPT® Code 81253

Official Description

GJB2 (gap junction protein, beta 2, 26kDa, connexin 26) (eg, nonsyndromic hearing loss) gene analysis; known familial variants

Common Language Description

The CPT® Code 81253 pertains to the molecular genetic testing of the GJB2 gene, which encodes the gap junction protein beta 2, also known as connexin 26. This gene analysis is specifically aimed at identifying known familial variants associated with nonsyndromic hearing loss (NSHL). The GJB2 gene plays a critical role in the formation of gap junctions, which are essential for cellular communication, allowing the transport of nutrients, ions, and signaling molecules between adjacent cells. Connexin 26, the protein produced by the GJB2 gene, is particularly important in the inner ear (cochlea) and the epidermis. Located on chromosome 13, the GJB2 gene has been linked to at least 90 identified mutations that can lead to a form of deafness known as NFNB1, which is inherited in an autosomal recessive manner. In this inheritance pattern, an individual who inherits one mutated copy of the gene becomes a carrier, while inheriting two mutated copies results in the manifestation of the condition. The mutations in the GJB2 gene typically disrupt the process by which sound waves are converted into nerve impulses, leading to hearing loss. Testing for known familial variants, such as 35delG or 30delG, is particularly relevant as these deletions occur between positions 30 and 35 of the gene and are most frequently observed in Caucasian populations. In contrast, Asian populations often exhibit a deletion at position 235 (235delC), while Ashkenazi Jewish populations are more likely to have a deletion at position 167 (167delT). All these mutations result in the production of an abnormally small protein that fails to effectively bridge the functional gap between cells. Additionally, some mutations may lead to the replacement of amino acids, resulting in unstable or dysfunctional proteins that cannot form proper gap junctions. Another form of hearing loss, DFNA3, is inherited in an autosomal dominant manner, where the presence of just one mutated gene is sufficient to cause the disease.

1. Indications

The GJB2 gene analysis (CPT® Code 81253) is indicated for individuals who are suspected of having nonsyndromic hearing loss (NSHL) due to known familial variants. This testing is particularly relevant for patients with a family history of hearing loss, as it can help identify genetic mutations that may contribute to the condition. The following conditions and scenarios may warrant the use of this genetic test:

Family History of Hearing Loss Individuals with a known family history of nonsyndromic hearing loss may benefit from testing to determine if they carry specific mutations in the GJB2 gene.
Diagnosis of Nonsyndromic Hearing Loss Patients presenting with unexplained hearing loss, particularly in the absence of other syndromic features, may be evaluated for GJB2 gene mutations.
Carrier Testing Individuals who are carriers of known familial variants may undergo testing to assess the risk of passing on hearing loss to their offspring.

2. Procedure

The procedure for conducting the GJB2 gene analysis involves several key steps to ensure accurate identification of known familial variants. The following procedural steps outline the process:

Step 1: Sample Collection A biological sample, typically blood or saliva, is collected from the patient. This sample serves as the source of DNA for the genetic analysis.
Step 2: DNA Extraction The DNA is extracted from the collected sample using standardized laboratory techniques. This step is crucial for isolating the genetic material needed for testing.
Step 3: Genetic Analysis The extracted DNA undergoes analysis to identify specific mutations in the GJB2 gene. This may involve techniques such as polymerase chain reaction (PCR) and sequencing to detect known familial variants.
Step 4: Interpretation of Results The results of the genetic analysis are interpreted by qualified laboratory personnel. They will determine if any known familial variants are present in the patient's DNA.
Step 5: Reporting A comprehensive report is generated, detailing the findings of the genetic analysis. This report is then provided to the healthcare provider for further discussion with the patient.

3. Post-Procedure

After the GJB2 gene analysis is completed, patients may receive counseling regarding the results, especially if a known familial variant is identified. This counseling can help patients understand the implications of the findings, including the potential for hereditary hearing loss and the risks for family members. Additionally, healthcare providers may discuss options for further testing or interventions based on the results. It is important for patients to have follow-up appointments to address any questions or concerns regarding their genetic testing and its impact on their health and family planning.

Short Descr	GJB2 GENE KNOWN FAM VARIANTS
Medium Descr	GJB2 GENE ANALYSIS KNOWN FAMILIAL VARIANTS
Long Descr	GJB2 (gap junction protein, beta 2, 26kDa, connexin 26) (eg, nonsyndromic hearing loss) gene analysis; known familial variants
Status Code	Statutory Exclusion (from MPFS, may be paid under other methodologies)
Global Days	XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC)	9 - Not Applicable
Multiple Procedures (51)	9 - Concept does not apply.
Bilateral Surgery (50)	9 - Concept does not apply.
Physician Supervisions	09 - Concept does not apply.
Assistant Surgeon (80, 82)	9 - Concept does not apply.
Co-Surgeons (62)	9 - Concept does not apply.
Team Surgery (66)	9 - Concept does not apply.
Diagnostic Imaging Family	99 - Concept Does Not Apply
CLIA Waived (QW)	No
APC Status Indicator	Service Paid under Fee Schedule or Payment System other than OPPS
Type of Service (TOS)	5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS)	T1H - Lab tests - other (non-Medicare fee schedule)
MUE	1
CCS Clinical Classification	234 - Pathology