CPT® Code 81337

Official Description

SMN1 (survival of motor neuron 1, telomeric) (eg, spinal muscular atrophy) gene analysis; known familial sequence variant(s)

Common Language Description

The CPT® Code 81337 pertains to the molecular genetic testing of the SMN1 (survival of motor neuron 1, telomeric) gene, specifically focusing on known familial sequence variant(s) associated with spinal muscular atrophy (SMA). SMA is a degenerative neuromuscular disease that is often fatal, characterized by the progressive loss of motor neurons in the spinal cord and brainstem, leading to muscle weakness and atrophy. The SMN1 gene, located on the long arm of chromosome 5 at position 13.2 (5q13.2), plays a crucial role in producing a protein essential for the survival of motor neurons. This protein facilitates the transport of signals from motor neurons to voluntary muscles, which are vital for functions such as walking, talking, and swallowing. In addition to the SMN1 gene, the SMN2 (survival of motor neuron 2, centromeric) gene may also be analyzed, as it is closely related and can influence the severity of SMA. The SMN1 gene is responsible for producing 85-90% of the functional protein, while the SMN2 gene contributes the remaining 10-15%, albeit with only one of its isoforms being fully functional. The presence of multiple copies of these genes can affect the risk of SMA transmission to offspring, with individuals potentially having between 0 to 3 copies of the SMN1 gene and up to 8 copies of the SMN2 gene. The analysis performed under CPT® Code 81337 is particularly significant when there is a known family history of SMA, as it allows for the identification of specific mutations that have already been documented in other family members. This targeted approach helps in assessing the risk for at-risk family members and provides valuable information for genetic counseling and family planning. Overall, this code is essential for understanding the genetic underpinnings of spinal muscular atrophy and for guiding clinical decisions based on familial genetic information.

1. Indications

The CPT® Code 81337 is indicated for use in situations where there is a known family history of spinal muscular atrophy (SMA). The specific indications for performing this genetic analysis include:

Family History of SMA - When a family member has been diagnosed with spinal muscular atrophy, testing can identify known familial sequence variants in the SMN1 gene.
Risk Assessment for At-Risk Family Members - The analysis helps determine whether other family members may be carriers of the genetic mutations associated with SMA, allowing for informed family planning and genetic counseling.

2. Procedure

The procedure for CPT® Code 81337 involves several key steps to ensure accurate detection of known familial sequence variants in the SMN1 gene. The steps are as follows:

Step 1: Sample Collection - A biological sample, typically blood or saliva, is collected from the individual being tested. This sample contains the DNA necessary for genetic analysis.
Step 2: DNA Extraction - The DNA is extracted from the collected sample using standard laboratory techniques to isolate the genetic material for analysis.
Step 3: Targeted Gene Analysis - The extracted DNA is subjected to molecular genetic testing specifically targeting the SMN1 gene. This involves analyzing specific sites on the gene that are known to harbor familial mutations.
Step 4: Variant Detection - The testing process identifies any known familial sequence variants present in the SMN1 gene. This is done by comparing the individual's genetic sequence to established databases of known mutations.
Step 5: Reporting Results - The results of the genetic analysis are compiled into a report that details the presence or absence of known familial variants. This report is then provided to the healthcare provider for further interpretation and counseling.

3. Post-Procedure

After the completion of the genetic testing associated with CPT® Code 81337, several post-procedure considerations are important. The results of the analysis will guide healthcare providers in discussing the implications of the findings with the patient and their family. If known familial variants are detected, genetic counseling may be recommended to help at-risk family members understand their potential risk for SMA. Additionally, the healthcare provider may discuss options for further testing or monitoring based on the results. It is also essential to consider the emotional and psychological impact of the results on the individual and their family, as the implications of genetic testing can be significant.

Short Descr	SMN1 GEN NOWN FAMIL SEQ VRNT
Medium Descr	SMN1 GENE ANALYSIS KNOWN FAMILIAL SEQ VARIANTS
Long Descr	SMN1 (survival of motor neuron 1, telomeric) (eg, spinal muscular atrophy) gene analysis; known familial sequence variant(s)
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