CPT® Code 81180

Official Description

ATXN3 (ataxin 3) (eg, spinocerebellar ataxia, Machado-Joseph disease) gene analysis, evaluation to detect abnormal (eg, expanded) alleles

Common Language Description

Molecular genetic testing is a critical procedure used to identify mutations in specific genes associated with various genetic disorders. In the case of CPT® Code 81180, the focus is on the ATXN3 (ataxin 3) gene, which is linked to spinocerebellar ataxia (SCA), particularly the most prevalent form known as Machado-Joseph disease. Spinocerebellar ataxia is characterized as a slowly progressive degenerative condition affecting the cerebellum and spinal cord, leading to a range of neurological symptoms. These symptoms can vary significantly based on which gene carries the mutation, but they often include uncoordinated gait (ataxia), muscle stiffness or spasms, tremors, and difficulties with speech (dysarthria) and swallowing (dysphagia). Additional manifestations may involve problems with hand-eye coordination, involuntary eye movements (nystagmus), vision issues, sleep disturbances, and challenges with learning, processing information, and memory retention. The ATXN3 gene is located on the long (q) arm of chromosome 14 at position 32.12 (14q32.12) and encodes an enzyme protein that plays a vital role in the ubiquitin proteasome system, which is responsible for the degradation and removal of damaged proteins from the body. In individuals with SCA3, the ATXN3 gene exhibits a unique DNA allele characterized by a trinucleotide repeat pattern of CAG (cytosine-adenine-guanine), which typically repeats fewer than 50 times. However, in cases of SCA3, this repeat expands to more than 50 times, leading to the associated symptoms of the disease. The onset of symptoms can occur at any age, from childhood to late adulthood, but they most commonly present during mid-adulthood. The CPT® Code 81180 specifically reports the analysis of the ATXN3 gene to evaluate and detect these abnormal (expanded) alleles, facilitating the diagnosis and understanding of the genetic basis of the condition.

1. Indications

The ATXN3 (ataxin 3) gene analysis is indicated for the evaluation of individuals who may be exhibiting symptoms associated with spinocerebellar ataxia (SCA), particularly those suggestive of Machado-Joseph disease. The following conditions and symptoms warrant consideration for this genetic testing:

Uncoordinated Gait (Ataxia) - Difficulty in maintaining balance and coordination while walking.
Muscle Stiffness or Spasms - Involuntary muscle contractions or rigidity that can affect movement.
Tremors - Involuntary shaking movements that can occur in various parts of the body.
Dysarthria - Difficulty in articulating words due to muscle control issues affecting speech.
Dysphagia - Difficulty in swallowing, which can lead to nutritional challenges.
Hand/Eye Coordination Problems - Challenges in coordinating visual input with hand movements.
Nystagmus - Involuntary eye movements that can affect vision stability.
Vision Problems - Various visual disturbances that may arise from neurological issues.
Sleep Disorders - Issues related to sleep patterns, including insomnia or excessive sleepiness.
Learning and Memory Difficulties - Challenges in processing information and retaining memories.

2. Procedure

The procedure for ATXN3 (ataxin 3) gene analysis involves several key steps to ensure accurate detection of abnormal alleles. The following outlines the procedural steps:

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 analysis.
Step 2: DNA Extraction - The DNA is extracted from the collected sample using standardized laboratory techniques to isolate the genetic material necessary for testing.
Step 3: PCR Amplification - Polymerase chain reaction (PCR) is employed to amplify the specific region of the ATXN3 gene that contains the CAG repeat sequence. This step is crucial for obtaining sufficient DNA for analysis.
Step 4: Allele Evaluation - The amplified DNA is then analyzed to detect the number of CAG repeats present in the ATXN3 gene. This evaluation determines whether the allele is normal or expanded.
Step 5: Result Interpretation - The results of the analysis are interpreted by a qualified geneticist or laboratory professional, who will assess the presence of abnormal (expanded) alleles indicative of SCA3.
Step 6: Reporting - A comprehensive report is generated, detailing the findings of the gene analysis, which is then communicated to the referring physician for further clinical decision-making.

3. Post-Procedure

After the ATXN3 gene analysis is completed, patients may receive counseling regarding the results, especially if abnormal alleles are detected. This counseling can include discussions about the implications of the findings, potential symptoms to monitor, and options for management or treatment. Patients may also be advised on the importance of genetic counseling for family members, as spinocerebellar ataxia can have hereditary implications. Follow-up appointments may be scheduled to discuss the results in detail and to plan any necessary interventions or supportive care based on the patient's specific symptoms and needs.

Short Descr	ATXN3 GENE DETC ABNOR ALLELE
Medium Descr	ATXN3 GENE ANALYSIS EVAL DETECT ABNORMAL ALLELES
Long Descr	ATXN3 (ataxin 3) (eg, spinocerebellar ataxia, Machado-Joseph disease) gene analysis, evaluation to detect abnormal (eg, expanded) alleles
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)	none
MUE	1

90	Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number.
GW	Service not related to the hospice patient's terminal condition
XS	Separate structure, a service that is distinct because it was performed on a separate organ/structure