CPT® Code 81325

Official Description

PMP22 (peripheral myelin protein 22) (eg, Charcot-Marie-Tooth, hereditary neuropathy with liability to pressure palsies) gene analysis; full sequence analysis

Common Language Description

The CPT® Code 81325 refers to the full sequence analysis of the PMP22 (peripheral myelin protein 22) gene, which is crucial for diagnosing conditions such as Charcot-Marie-Tooth disease and hereditary neuropathy with liability to pressure palsies. This molecular genetic testing aims to identify specific mutations within the PMP22 gene located on chromosome 17. The PMP22 gene encodes a protein that is an essential component of the myelin sheath surrounding nerve cells, which is vital for the proper transmission of nerve impulses. The protein is produced by Schwann cells, which are responsible for the formation and maintenance of the myelin sheath. Mutations in the PMP22 gene can lead to various forms of neuropathy, with inheritance patterns that may be autosomal recessive or autosomal dominant. In the case of autosomal recessive inheritance, an individual must inherit a mutated gene from both parents to exhibit symptoms of the disease. Conversely, in autosomal dominant inheritance, only one copy of the mutated gene is sufficient to cause the disorder. The most prevalent form of Charcot-Marie-Tooth disease, known as Type 1A, is characterized by a duplication of the PMP22 gene, resulting in an overproduction of the PMP22 protein. This overproduction disrupts the normal processing of the protein, leading to a reduction in functional PMP22 levels, which in turn decreases myelin integrity and impairs nerve function. Additionally, hereditary neuropathy with liability to pressure palsies is often associated with a reduction in gene dosage, where one copy of the PMP22 gene is lost, leading to insufficient levels of the protein. This condition can also arise from mutations that produce a smaller, unstable version of the PMP22 protein, which degrades rapidly and fails to protect the myelin sheath, making it more susceptible to damage from pressure. The full sequence analysis provided by CPT® Code 81325 is essential for identifying these mutations, thereby facilitating accurate diagnosis and management of these hereditary neuropathies.

1. Indications

The full sequence analysis of the PMP22 gene, as indicated by CPT® Code 81325, is performed for the following conditions:

Charcot-Marie-Tooth Disease - A hereditary neuropathy characterized by progressive muscle weakness and atrophy, sensory loss, and foot deformities, often associated with mutations in the PMP22 gene.
Hereditary Neuropathy with Liability to Pressure Palsies - A condition that leads to recurrent episodes of weakness and sensory loss due to pressure on nerves, often linked to reduced gene dosage or mutations affecting the PMP22 protein.

2. Procedure

The procedure for conducting a full sequence analysis of the PMP22 gene involves several critical steps to ensure accurate identification of mutations:

Step 1: Sample Collection - A biological sample, typically blood or saliva, is collected from the patient. This sample contains the DNA necessary for genetic analysis.
Step 2: DNA Extraction - The DNA is extracted from the collected sample using standardized laboratory techniques to isolate the genetic material for analysis.
Step 3: Amplification of PMP22 Gene - Polymerase chain reaction (PCR) is employed to amplify the specific regions of the PMP22 gene, ensuring that there is sufficient DNA for detailed analysis.
Step 4: Sequencing - The amplified DNA is subjected to sequencing, which determines the exact order of nucleotides in the PMP22 gene. This step is crucial for identifying any mutations present.
Step 5: Data Analysis - The sequencing data is analyzed using bioinformatics tools to compare the patient's PMP22 gene sequence against a reference sequence, identifying any variations or mutations that may be pathogenic.
Step 6: Reporting Results - The findings are compiled into a comprehensive report that details any identified mutations, their potential implications for the patient, and recommendations for further action or testing if necessary.

3. Post-Procedure

After the full sequence analysis of the PMP22 gene is completed, the patient may receive counseling regarding the results. If mutations are identified, healthcare providers may discuss the implications for the patient's health, potential treatment options, and the risk of transmission to family members. Follow-up testing may be recommended for family members, especially if a hereditary condition is confirmed. Additionally, the healthcare team may provide resources and support for managing symptoms associated with Charcot-Marie-Tooth disease or hereditary neuropathy with liability to pressure palsies.

Short Descr	PMP22 GENE FULL SEQUENCE
Medium Descr	PMP22 GENE ANALYSIS FULL SEQUENCE ANALYSIS
Long Descr	PMP22 (peripheral myelin protein 22) (eg, Charcot-Marie-Tooth, hereditary neuropathy with liability to pressure palsies) gene analysis; full sequence analysis
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

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.
XU	Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
GW	Service not related to the hospice patient's terminal condition
59	Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
GA	Waiver of liability statement issued as required by payer policy, individual case
XS	Separate structure, a service that is distinct because it was performed on a separate organ/structure