CPT® Code 81205

Official Description

BCKDHB (branched-chain keto acid dehydrogenase E1, beta polypeptide) (eg, maple syrup urine disease) gene analysis, common variants (eg, R183P, G278S, E422X)

Common Language Description

The CPT® Code 81205 pertains to the molecular genetic testing of the BCKDHB gene, which encodes the branched-chain keto acid dehydrogenase E1, beta polypeptide. This gene analysis is particularly significant in the context of diagnosing Maple syrup urine disease (MSUD), a rare autosomal recessive disorder. MSUD arises from mutations in the BCKDHB gene inherited from both parents, leading to a deficiency in the enzyme complex responsible for the metabolism of branched-chain amino acids, specifically leucine, isoleucine, and valine. The BCKDHB gene is located on chromosome 6 and has over 40 identified mutations, with common variants including R183P, G278S, and E422X. The incidence of MSUD is estimated at 1 in 185,000 newborns globally, with higher prevalence in certain populations, such as those of Ashkenazi Jewish descent and Old Order Mennonites. The enzyme complex formed by the BCKDHB gene is crucial for breaking down dietary proteins, and its dysfunction leads to toxic accumulation of amino acids and their byproducts, which can severely affect neurological function. Symptoms of MSUD typically manifest in infancy and can include feeding difficulties, developmental delays, lethargy, and seizures, particularly during periods of stress. Genetic testing for the BCKDHB gene is essential for identifying carriers and confirming diagnoses, thereby guiding treatment strategies that focus on dietary management to prevent toxic buildup.

1. Indications

The BCKDHB gene analysis (CPT® Code 81205) is indicated for the following conditions:

Maple Syrup Urine Disease (MSUD) - This genetic test is performed to confirm a diagnosis of MSUD in individuals presenting with symptoms such as feeding problems, developmental delays, lethargy, seizures, and coma.
Carrier Testing - The test is also indicated for identifying carriers of the BCKDHB gene mutation, particularly in individuals with a family history of MSUD or those belonging to populations with a higher incidence of the disease.

2. Procedure

The procedure for conducting the BCKDHB gene analysis involves several key steps:

Sample Collection - A biological sample, typically blood or saliva, is collected from the individual undergoing testing. This sample contains the DNA necessary for genetic analysis.
DNA Extraction - The DNA is extracted from the collected sample using standard laboratory techniques to isolate the genetic material for analysis.
Mutation Analysis - The extracted DNA is subjected to molecular genetic testing to identify specific mutations in the BCKDHB gene. This may involve techniques such as polymerase chain reaction (PCR) and sequencing to detect common variants like R183P, G278S, and E422X.
Data Interpretation - The results of the genetic analysis are interpreted by qualified laboratory personnel, who assess the presence of mutations and their implications for the individual’s health.
Reporting - A comprehensive report is generated, detailing the findings of the genetic test, including whether any mutations were identified and their potential association with Maple syrup urine disease.

3. Post-Procedure

After the BCKDHB gene analysis is completed, the individual may receive counseling regarding the results, especially if a mutation is identified. If the test confirms a diagnosis of Maple syrup urine disease, immediate dietary management is crucial to prevent toxic accumulation of amino acids. This typically involves implementing a protein-free diet and may require ongoing monitoring and adjustments based on the individual's health status. Additionally, genetic counseling may be recommended for family members to discuss the implications of carrier status and the risk of passing the condition to future offspring.

Short Descr	BCKDHB GENE
Medium Descr	BCKDHB GENE ANALYSIS COMMON VARIANTS
Long Descr	BCKDHB (branched-chain keto acid dehydrogenase E1, beta polypeptide) (eg, maple syrup urine disease) gene analysis, common variants (eg, R183P, G278S, E422X)
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)	T2D - Other tests - other
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.
GW	Service not related to the hospice patient's terminal condition