CPT® Code 81302

Official Description

MECP2 (methyl CpG binding protein 2) (eg, Rett syndrome) gene analysis; full sequence analysis

Common Language Description

The CPT® Code 81302 refers to the full sequence analysis of the MECP2 (methyl CpG binding protein 2) gene, which is crucial for diagnosing conditions such as Rett syndrome. This molecular genetic testing aims to identify specific mutations within the MECP2 gene, which encodes a protein essential for normal nerve cell functioning. The MECP2 protein plays a significant role in the brain, acting as both a transcriptional repressor and activator, and is found in high concentrations in neurons, where it is vital for forming synapses—connections that facilitate communication between nerve cells. The MECP2 gene is located on the X chromosome and is primarily associated with paternal-linked autosomal dominant mutations. Mutations in the MECP2 gene are implicated in most cases of Rett syndrome, a progressive neurological and developmental disorder that predominantly affects females. Typically, individuals with classic Rett syndrome exhibit normal growth and development for the first 6 to 18 months of life, after which they begin to experience severe challenges in language, communication, learning, coordination, and overall brain function. There are atypical forms of the syndrome as well, including a mild variant where speech is preserved and a severe variant that lacks any period of normal development. Research indicates that approximately 90% of classic Rett syndrome cases arise from new ('de novo') mutations, with no prior family history of the disorder. While males with the MECP2 mutation often do not survive past infancy, a small number of males with classic Rett syndrome have been identified, typically possessing an extra X chromosome that allows for the production of sufficient MECP2 protein for survival. The full sequence analysis performed under CPT® Code 81302 involves comparing gene segments to identify similarities, differences, and relationships, as well as studying intrinsic features to locate active sites and gene structures. This analysis can reveal genetic markers by identifying point mutations or single nucleotide polymorphisms (SNPs). Various types of mutations, including point mutations and insertion/deletion mutations, have been documented in individuals diagnosed with Rett syndrome. Additionally, MECP2 mutations have been associated with moderate to severe X-linked mental retardation (XLMR), neonatal encephalopathy, and certain autism cases, highlighting the gene's significance in a range of neurological conditions.

1. Indications

The MECP2 gene analysis is indicated for the following conditions and scenarios:

Rett Syndrome Identification of mutations in the MECP2 gene is crucial for diagnosing Rett syndrome, a progressive neurological disorder primarily affecting females.
Neurological Developmental Disorders MECP2 mutations have been associated with various neurological and developmental disorders, including moderate to severe X-linked mental retardation (XLMR).
Neonatal Encephalopathy The analysis may be indicated in cases of severe brain dysfunction known as neonatal encephalopathy, where MECP2 mutations have been identified.
Autism Spectrum Disorders Some individuals with autism have been found to carry mutations in the MECP2 gene, warranting genetic testing.
Familial Testing When a family member is diagnosed with an MECP2 mutation, testing is recommended for other relatives to identify common or familial variants.

2. Procedure

The procedure for MECP2 gene analysis involves several detailed steps to ensure accurate identification of mutations:

Sample Collection A biological sample, typically blood or saliva, is collected from the individual undergoing testing. This sample contains the DNA necessary for analysis.
DNA Extraction The DNA is extracted from the collected sample using standardized laboratory techniques to isolate the genetic material for further analysis.
Full Sequence Analysis The extracted DNA undergoes full sequence analysis, which involves comparing the MECP2 gene segments to identify any mutations. This step includes examining the gene's structure, introns, exons, and regulatory elements.
Mutation Identification The analysis focuses on identifying point mutations, insertion/deletion mutations, and single nucleotide polymorphisms (SNPs) that may be present in the MECP2 gene.
Data Interpretation The results of the analysis are interpreted by geneticists or molecular biologists, who assess the significance of any identified mutations in relation to Rett syndrome and other associated disorders.
Reporting A comprehensive report is generated, detailing the findings of the analysis, including any identified mutations and their potential implications for the patient and their family.

3. Post-Procedure

After the MECP2 gene analysis is completed, several post-procedure considerations are important:

Patients and their families may receive genetic counseling to discuss the implications of the test results, especially if a mutation is identified. This counseling can help families understand the nature of the disorder, potential health implications, and options for family planning. Additionally, if a mutation is found, testing may be recommended for other family members to determine if they carry the same mutation. Follow-up appointments may be necessary to monitor any developmental concerns or to provide support for managing symptoms associated with Rett syndrome or other related conditions.

Short Descr	MECP2 GENE FULL SEQ
Medium Descr	MECP2 GENE ANALYSIS FULL SEQUENCE
Long Descr	MECP2 (methyl CpG binding protein 2) (eg, Rett syndrome) 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
XS	Separate structure, a service that is distinct because it was performed on a separate organ/structure
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
GV	Attending physician not employed or paid under arrangement by the patient's hospice provider