Name of the Procedure:

MSH2 (mutS homolog 2, colon cancer, nonpolyposis type 1) Gene Analysis; Duplication/Deletion Variants
Common name(s): MSH2 Genetic Testing, Lynch Syndrome Genetic Testing

Summary

MSH2 gene analysis for duplication/deletion variants is a genetic test used to identify specific changes in the MSH2 gene that may contribute to hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome. This test looks for large deletions or duplications in the MSH2 gene.

Purpose

This genetic test addresses the identification of hereditary non-polyposis colorectal cancer (HNPCC or Lynch syndrome). The primary goal is to detect duplications or deletions in the MSH2 gene that can increase the risk of colorectal and other types of cancers. Early identification allows for prompt intervention and tailored surveillance.

Indications

• Family history of HNPCC/Lynch syndrome-related cancers (e.g., colorectal, endometrial)
• Early onset colorectal cancer (typically before age 50)
• Multiple Lynch syndrome-associated cancers in a single individual or family
• Previous inconclusive MSH2 genetic testing

Preparation

• No fasting or special dietary modifications are required.
• Patients should inform their healthcare provider of all medications and supplements they are taking.
• A pre-test genetic counseling session is recommended to discuss the potential outcomes and implications of the test.

Procedure Description

1. Sample Collection: A blood sample is drawn from the patient.
2. DNA Isolation: DNA is extracted from the collected blood sample.
3. Genetic Testing: The DNA undergoes analysis using techniques like Multiplex Ligation-dependent Probe Amplification (MLPA) to detect large deletions or duplications in the MSH2 gene.
4. Result Interpretation: A genetic specialist interprets the results, identifying any significant gene alterations.

Duration

The blood draw takes about 5-10 minutes. The overall turnaround time for results can range from a few weeks to a few months, depending on the laboratory.

Setting

The blood draw is typically performed in an outpatient clinic, doctor's office, or genetic testing facility. DNA analysis is conducted in a specialized genetic laboratory.

Personnel

• Phlebotomist (for blood draw)
• Clinical Geneticist or Molecular Pathologist (for DNA analysis and interpretation)
• Genetic Counselor (for pre- and post-test counseling)

Risks and Complications

• Bruising or minor pain at the blood draw site
• Emotional impact of test results
• Misinterpretation of test results without proper genetic counseling

Benefits

• Early identification of Lynch syndrome enables proactive cancer screening and prevention strategies.
• Informs patient and family members about their risk of developing cancer.
• Facilitates personalized medical management plans.

Recovery

• No physical recovery is needed for the blood draw itself.
• Patients are advised to follow up with their healthcare provider or genetic counselor to discuss the test results.

Alternatives

• Comprehensive genetic panel testing for other mismatch repair (MMR) genes (e.g., MLH1, MSH6, PMS2)
• Traditional risk assessment based on family history without genetic testing
• Surveillance colonoscopy and other cancer screening methods without genetic confirmation

Patient Experience

During the blood draw, the patient might feel a brief pinch or stinging sensation. After the test, they may feel anxious or nervous about the results. Most discomfort is minor and short-lived. Genetic counseling helps manage emotional responses and provides support throughout the process.