APC (adenomatous polyposis coli) (eg, familial adenomatosis polyposis [FAP], attenuated FAP) gene analysis; known familial variants
CPT4 code
Name of the Procedure:
APC Gene Analysis; Known Familial Variants (Adenomatous Polyposis Coli, Familial Adenomatosis Polyposis [FAP], Attenuated Familial Adenomatosis Polyposis [AFAP])
Summary
APC gene analysis is a genetic test used to identify specific known familial variants in the APC gene, which is associated with conditions like Familial Adenomatosis Polyposis (FAP) and its milder form, Attenuated FAP (AFAP). This test helps in diagnosing and managing these hereditary conditions.
Purpose
The procedure addresses hereditary cancer syndromes, particularly FAP and AFAP. The primary goal is to detect known familial variants in the APC gene, enabling early diagnosis, risk assessment, and tailored management plans for patients and their families.
Indications
- Family history of FAP or AFAP
- Individuals with multiple colorectal polyps
- Early onset of colorectal cancer
- Relatives of individuals known to carry a pathogenic APC variant
- Genetic counseling and family planning
Preparation
- No special preparation, fasting, or medication adjustments typically required.
- Pre-test genetic counseling is recommended.
- Blood sample collection or buccal swab.
Procedure Description
- A blood sample is drawn from the patient or a buccal swab is taken.
- DNA is extracted from the collected sample.
- The DNA is then analyzed using techniques like PCR (Polymerase Chain Reaction) and sequencing to identify the known familial variants in the APC gene.
- Results are interpreted by a geneticist.
No anesthesia or sedation is required.
Duration
- Sample collection: 5-10 minutes.
- Laboratory analysis: 2-4 weeks to obtain results.
Setting
The sample collection can be done in a hospital, outpatient clinic, or specialized genetic testing center.
Personnel
- Phlebotomist or nurse (for sample collection)
- Geneticist and laboratory technicians (for analysis)
- Genetic counselor (for result interpretation and genetic counseling)
Risks and Complications
- Minimal risks associated with blood draw, such as slight bruising or infection at the needle site.
- Psychological impact of test results.
Benefits
- Early detection and diagnosis of FAP or AFAP.
- Allows for proactive management and surveillance.
- Informs family members about their potential risk and the need for genetic testing.
Recovery
- No physical recovery required from the procedure itself.
- Psychological support may be needed depending on the results.
Alternatives
- Comprehensive APC gene sequencing (for unknown variants)
- Colonoscopic surveillance in high-risk individuals without prior genetic testing
Patient Experience
- Minimal discomfort during sample collection.
- Anxiety or relief depending on the test outcome.
- Access to genetic counseling for support and guidance.
The APC gene analysis for known familial variants is a vital tool for managing hereditary cancer risk, providing crucial information for patients and their families to take informed health decisions.