MLH1 (mutL homolog 1, colon cancer, nonpolyposis type 2) (eg, hereditary non-polyposis colorectal cancer, Lynch syndrome) gene analysis; promoter methylation analysis
CPT4 code
Name of the Procedure:
MLH1 (mutL homolog 1, colon cancer, nonpolyposis type 2) Gene Analysis; Promoter Methylation Analysis
Summary
This test analyzes the MLH1 gene to detect specific changes in its promoter region through methylation analysis. It helps identify hereditary non-polyposis colorectal cancer, commonly known as Lynch syndrome.
Purpose
The procedure targets the identification of Lynch syndrome, a condition that significantly increases the risk of colorectal cancer and other cancers. The goals are to confirm the diagnosis, guide treatment decisions, and inform at-risk family members.
Indications
Patients with a family history of Lynch syndrome or colorectal cancer, especially those diagnosed at a young age, may be recommended this test. Individuals showing symptoms of colorectal cancer or related cancers may also need this procedure.
Preparation
No extensive preparation is typically required. Patients may need to provide a detailed medical and family history. In some cases, a blood sample or tissue biopsy might be needed.
Procedure Description
- A sample is collected either via blood draw or tissue biopsy.
- Laboratory technicians extract DNA from the sample.
- Specific chemicals are applied to detect methylation in the MLH1 gene's promoter region.
- Results are analyzed to determine the presence of abnormal gene methylation.
Standard laboratory equipment, including DNA extraction and methylation detection tools, is used. No anesthesia or sedation is required as the process is minimally invasive.
Duration
The procedure itself is brief, usually taking a few minutes for sample collection. Laboratory analysis may take several days to complete.
Setting
Typically performed in a hospital or specialized laboratory.
Personnel
Geneticists, molecular biologists, and lab technicians are primarily involved in the analysis. Initial sample collection may be done by a nurse or phlebotomist.
Risks and Complications
Minimal risks are associated with the sample collection, such as minor bruising or discomfort at the blood draw or biopsy site. Rarely, infection could occur at the biopsy site.
Benefits
Identifying abnormal MLH1 gene methylation can provide crucial information for early intervention and tailored treatment strategies for those with Lynch syndrome. Early identification can help in the timely management and reduction of cancer risks.
Recovery
No significant recovery time is needed. Patients can resume their normal activities immediately after sample collection. Follow-up is often dependent on the test results and subsequent medical advice.
Alternatives
Alternative options include broader genetic testing for other mismatch repair genes associated with Lynch syndrome. Stool DNA tests or colonoscopy might be suggested as complementary screening methods. Each option has variable accuracy, invasiveness, and scope.
Patient Experience
The patient may experience slight discomfort during sample collection. Post-procedure pain is minimal and typically managed with over-the-counter pain relievers if necessary. Patients may feel anxious awaiting results and should receive counseling and support as needed.