MLH1 (mutL homolog 1, colon cancer, nonpolyposis type 2) (eg, hereditary non-polyposis colorectal cancer, Lynch syndrome) gene analysis; known familial variants
CPT4 code
Name of the Procedure:
MLH1 (mutL homolog 1, colon cancer, nonpolyposis type 2) Gene Analysis; Known Familial Variants
Common name(s): MLH1 Gene Test, Lynch Syndrome Genetic Test
Summary
The MLH1 gene analysis is a genetic test used to identify specific known variants within the MLH1 gene that are associated with Lynch syndrome, a type of hereditary non-polyposis colorectal cancer. This test helps in determining if an individual has inherited variants that increase their risk of developing colorectal and other types of cancer.
Purpose
The procedure addresses the genetic susceptibility to Lynch syndrome, which significantly increases the risk of developing colorectal cancer and other cancers. The goal is to identify if a patient carries a known familial variant of the MLH1 gene, thereby allowing for early intervention, personalized screening strategies, and informed family planning decisions.
Indications
- Family history of Lynch syndrome or known variants of the MLH1 gene.
- Personal history of colorectal cancer or other cancers associated with Lynch syndrome.
- Early-onset colorectal cancer (diagnosed under age 50).
- Multiple relatives with colorectal or Lynch syndrome-related cancers.
Preparation
- No special preparation like fasting is required.
- Patients may need to provide a detailed family medical history.
- Genetic counseling is often recommended before and after the test to understand the implications of the results.
Procedure Description
- Sample Collection: A blood sample is usually taken from the patient. Alternatively, a saliva sample or a buccal swab (swabbing the inside of the cheek) can be used.
- DNA Extraction: The sample is sent to a laboratory where DNA is extracted.
- Gene Analysis: The extracted DNA is analyzed using various genetic testing methods such as Polymerase Chain Reaction (PCR) and DNA sequencing to identify the presence of known familial MLH1 variants.
- Result Interpretation: The results are interpreted by a geneticist and shared with the patient through a post-test counseling session.
Duration
The sample collection process takes about 15-30 minutes. The analysis can take several weeks, generally 2-4 weeks, depending on the laboratory's turnaround time.
Setting
The sample is collected in an outpatient clinic, doctor’s office, or a genetic counseling center and sent to a specialized genetic testing laboratory for analysis.
Personnel
- Genetic counselors
- Laboratory technicians
- Physicians or specialized healthcare professionals for result interpretation and consultation
Risks and Complications
The risks associated with this procedure are minimal:
- Minor discomfort or bruising at the blood draw site.
- Emotional distress from learning genetic risk information.
Benefits
- Early detection of Lynch syndrome, which allows for proactive health management.
- Personalized prevention and screening strategies to reduce cancer risk.
- Informed family planning and risk assessment for family members.
Recovery
No physical recovery is needed. Patients may need counseling and support to understand and cope with the results.
Alternatives
- Comprehensive genetic testing, which includes analysis of multiple genes associated with colorectal cancer.
- Regular colorectal cancer screening (colonoscopy) without prior genetic testing.
- Surveillance programs for high-risk individuals based on family history alone.
Patient Experience
- The sample collection is quick and relatively painless, with minor discomfort if blood is drawn.
- After receiving results, patients may experience a range of emotions; genetic counseling provides support and information to help manage any emotional impact.
- Patients will receive information on next steps and ongoing preventive measures tailored to their genetic risk.
Pain management and comfort measures during sample collection are minimal, as the procedure is quick with low discomfort levels.