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Molecular genetic testing is a critical procedure used to identify mutations in specific genes associated with various genetic disorders, including spinocerebellar ataxia (SCA). This condition is characterized by a progressive degeneration of the cerebellum and spinal cord, leading to a range of neurological symptoms. The ATXN1 gene, which is the focus of this analysis, is located on the short (p) arm of chromosome 6 at position 22.3 (6p22.3). It encodes the protein ataxin 1, which plays a role in neuronal function and is distributed throughout the body. In individuals with SCA, mutations in the ATXN1 gene can lead to an abnormal expansion of a specific DNA sequence known as a trinucleotide repeat, which consists of the nucleotides cytosine, adenine, and guanine (CAG). Normally, this repeat occurs between 4 to 39 times; however, in SCA1, the repeat can expand to between 40 to 80 times or more. The presence of these expanded alleles is associated with the onset of symptoms, which can include uncoordinated gait (ataxia), muscle stiffness, tremors, dysarthria (difficulty speaking), dysphagia (difficulty swallowing), and various cognitive challenges. Symptoms typically emerge in mid-adulthood, although they can appear earlier in individuals with a higher number of repeats. The CPT® Code 81178 specifically reports the analysis of the ATXN1 gene to evaluate and detect these abnormal (expanded) alleles, facilitating diagnosis and management of the condition.
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The ATXN1 gene analysis is indicated for individuals who exhibit symptoms consistent with spinocerebellar ataxia (SCA). These symptoms may include:
The procedure for ATXN1 gene analysis involves several key steps to ensure accurate detection of abnormal alleles. First, a sample is collected from the patient, typically through a blood draw or saliva sample, which contains the DNA necessary for analysis. Next, the DNA is extracted from the sample and prepared for testing. This preparation may involve amplifying the specific regions of the ATXN1 gene that are of interest, particularly the area containing the CAG repeat sequence. Following amplification, the DNA is subjected to sequencing or other molecular techniques to identify the number of CAG repeats present in the gene. The results are then analyzed to determine if the number of repeats falls within the normal range (4-39 repeats) or if there is an expansion indicative of spinocerebellar ataxia (40-80 repeats or more). Finally, the findings are compiled into a report that details the presence of any abnormal alleles, which can then be used by healthcare providers to inform diagnosis and management of the patient's condition.
After the ATXN1 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 genetic counseling, particularly if there is a family history of spinocerebellar ataxia, as this condition can have hereditary components. 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. Additionally, healthcare providers may recommend monitoring for the development of symptoms associated with SCA, as early intervention can be beneficial in managing the condition.
| Short Descr | ATXN1 GENE DETC ABNOR ALLELE | Medium Descr | ATXN1 GENE ANALYSIS EVAL DETECT ABNORMAL ALLELES | Long Descr | ATXN1 (ataxin 1) (eg, spinocerebellar ataxia) 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. | GA | Waiver of liability statement issued as required by payer policy, individual case | GW | Service not related to the hospice patient's terminal condition | GZ | Item or service expected to be denied as not reasonable and necessary |
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| 2019-01-01 | Added | Added |
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