CPT® Code 81303

Official Description

MECP2 (methyl CpG binding protein 2) (eg, Rett syndrome) gene analysis; known familial variant

Common Language Description

The CPT® Code 81303 pertains to the molecular genetic testing of the MECP2 gene, specifically focusing on the analysis of a known familial variant associated with Rett syndrome. The MECP2 gene is crucial for producing a protein that is essential for normal nerve cell function, acting as both a transcriptional repressor and activator within the brain. This protein is predominantly found in neurons, where it plays a vital role in the formation of synapses, which are the connections that facilitate communication between nerve cells. The MECP2 gene is located on the X chromosome and is primarily linked to paternal inheritance, exhibiting an autosomal dominant mutation pattern. Rett syndrome, a progressive neurological and developmental disorder, is most commonly observed in females. The classic presentation of this condition includes a period of normal growth and development for the first 6 to 18 months, followed by a decline in language, communication, learning, coordination, and overall brain function. There are atypical forms of Rett syndrome as well, which may present with preserved speech or a lack of normal developmental milestones. Notably, research indicates that approximately 90% of classic Rett syndrome cases arise from new ('de novo') mutations of the MECP2 gene, with no prior family history of the disorder. While males with the MECP2 mutation typically do not survive past infancy, a small number of males with classic Rett syndrome have been identified, often possessing an extra X chromosome that allows for the production of sufficient MECP2 protein for survival. The analysis performed under CPT® Code 81303 is critical for identifying familial variants of the MECP2 gene, enabling genetic mapping among family members when a mutation has been identified in an individual. This testing is essential for understanding the inheritance patterns and potential risks for relatives. The MECP2 gene has also been implicated in other conditions, including moderate to severe X-linked mental retardation, neonatal encephalopathy, and certain autism cases, highlighting its significance in various neurological disorders.

1. Indications

The MECP2 gene analysis using CPT® Code 81303 is indicated for the following conditions:

Rett Syndrome - A progressive neurological and developmental disorder primarily affecting females, characterized by normal early development followed by a decline in cognitive and motor skills.
Familial Variant Testing - When a known MECP2 gene mutation has been identified in an individual, testing is indicated for family members to determine the presence of the same or related mutations.
Moderate to Severe X-Linked Mental Retardation (XLMR) - MECP2 mutations have been associated with this condition, warranting genetic testing for affected individuals.
Neonatal Encephalopathy - Some males with severe brain dysfunction have been found to have MECP2 mutations, indicating the need for genetic analysis.
Autism Spectrum Disorders - In certain cases, MECP2 mutations have been identified in individuals exhibiting characteristics of autism, suggesting the relevance of genetic testing.

2. Procedure

The procedure for CPT® Code 81303 involves the following steps:

Sample Collection - A blood sample is collected from the individual being tested, which serves as the source of DNA for analysis.
DNA Extraction - The DNA is extracted from the collected blood sample using standard laboratory techniques to isolate the genetic material for testing.
Genetic Analysis - The extracted DNA is analyzed specifically for the known familial variant of the MECP2 gene. This involves comparing the individual's DNA sequence to the reference sequence to identify any mutations or variations.
Interpretation of Results - The results of the genetic analysis are interpreted to determine whether the familial variant is present in the individual. This interpretation is crucial for understanding the implications for the individual and their family members.
Reporting - A detailed report is generated, summarizing the findings of the genetic analysis, including the presence or absence of the known familial variant and any relevant genetic counseling recommendations.

3. Post-Procedure

After the procedure associated with CPT® Code 81303, the following post-procedure considerations are important:

Patients may receive genetic counseling based on the results of the MECP2 gene analysis. If a familial variant is identified, family members may also be advised to undergo testing to assess their risk of carrying the mutation. The results can provide valuable information for family planning and understanding the potential for the disorder to manifest in future generations. Additionally, healthcare providers may discuss the implications of the findings, including the potential for early intervention and management strategies for any associated conditions. Follow-up appointments may be scheduled to review the results and discuss any necessary next steps.

Short Descr	MECP2 GENE KNOWN VARIANT
Medium Descr	MECP2 GENE ANALYSIS KNOWN FAMILIAL VARIANT
Long Descr	MECP2 (methyl CpG binding protein 2) (eg, Rett syndrome) gene analysis; known familial variant
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