MSH6 (mutS homolog 6 [E. coli]) (eg, hereditary non-polyposis colorectal cancer, Lynch syndrome) gene analysis; full sequence analysis
CPT4 code
Name of the Procedure:
MSH6 (mutS homolog 6 [E. coli]) Gene Analysis, Full Sequence Analysis
Summary
The MSH6 gene analysis is a genetic test that examines the full sequence of the MSH6 gene to identify mutations. This gene is linked to hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome. The test helps in diagnosing the predisposition to this form of cancer.
Purpose
The MSH6 gene analysis helps detect mutations in the MSH6 gene, which are associated with an increased risk of Lynch syndrome. The primary goal is to identify individuals at risk for hereditary non-polyposis colorectal cancer and other associated cancers, enabling early intervention and preventive measures.
Indications
- Family history of colorectal cancer or Lynch syndrome-related cancers (endometrial, ovarian, gastric, etc.).
- Personal history of colorectal or other associated cancers at an early age.
- Presence of multiple primary cancers in one individual.
- Tumor testing that shows microsatellite instability (MSI) or mismatch repair (MMR) deficiency.
Preparation
- No specific preparation such as fasting or medication adjustment is typically required.
- A blood sample or cheek swab may be collected for DNA analysis.
- Genetic counseling is recommended before and after the test to understand the implications.
Procedure Description
- Sample Collection: A blood sample is drawn from the patient or a cheek swab is taken.
- DNA Extraction: DNA is extracted from the collected sample in a laboratory.
- Sequencing: The full sequence of the MSH6 gene is analyzed using next-generation sequencing or another suitable method.
- Data Analysis: Bioinformatics tools are used to identify any mutations or genetic abnormalities in the MSH6 gene.
- Reporting: A detailed report is generated, indicating whether any pathogenic mutations have been identified.
Duration
The sample collection process takes a few minutes. The full analysis in the lab typically takes a few weeks to complete, depending on the testing facility.
Setting
The sample collection can be performed in a hospital, outpatient clinic, or a specialized genetic testing lab. The actual DNA analysis is carried out in a laboratory setting.
Personnel
- Phlebotomist or nurse for sample collection.
- Laboratory technicians and geneticists for DNA analysis.
- Genetic counselor to discuss results and implications with the patient.
Risks and Complications
- Bruising or slight discomfort at the blood draw site.
- Emotional impact of test results, particularly if a pathogenic mutation is found.
- Privacy concerns regarding genetic information.
Benefits
- Identification of Lynch syndrome risk, enabling proactive cancer screening and prevention.
- Informed decision-making about management and surveillance.
- Family members can also be tested if a mutation is found, aiding in risk assessment for relatives.
Recovery
- No physical recovery is required as the test is non-invasive.
- Psychological support might be necessary depending on the test results and their impact.
Alternatives
- Tumor testing for microsatellite instability (MSI) or immunohistochemistry (IHC) for mismatch repair proteins.
- Other genetic tests if another Lynch syndrome-related gene is suspected.
- Regular cancer screenings without genetic testing, although this might not be as targeted or effective.
Patient Experience
- The sample collection process is quick and usually painless, though there may be minor discomfort.
- Waiting for results can be a period of anxiety, and support from a genetic counselor can be beneficial.
- Upon receiving results, patients might experience a range of emotions from relief to concern, especially if a mutation is identified.