The primary way to definitively test for Gardner's syndrome is through genetic testing to identify mutations in the APC gene.
Here's a breakdown:
- Genetic Testing: This is the most accurate method. A blood sample is typically taken and analyzed in a lab to look for specific mutations within the APC (adenomatous polyposis coli) gene.
- This gene is responsible for suppressing tumor growth. Mutations in this gene significantly increase the risk of developing the characteristic polyps associated with Gardner's syndrome.
- When is genetic testing recommended?
- Family History: If there's a known family history of Gardner's syndrome or Familial Adenomatous Polyposis (FAP), genetic testing is strongly recommended for individuals at risk.
- Numerous Colon Polyps: If a colonoscopy reveals a high number of polyps (typically more than 100) in the colon and rectum, genetic testing is often indicated to confirm a diagnosis or determine the risk of Gardner's syndrome.
It's important to note that while genetic testing is definitive, diagnosis sometimes involves a combination of clinical findings and family history, even before genetic confirmation. These findings can include:
-
Physical Examinations: Looking for other characteristic signs of Gardner's syndrome, such as:
- Epidermoid cysts
- Osteomas (benign bone tumors, often in the skull or jaw)
- Dental abnormalities
- Desmoid tumors (noncancerous growths in connective tissue)
- Congenital Hypertrophy of the Retinal Pigment Epithelium (CHRPE)
-
Colonoscopy/Sigmoidoscopy: These procedures allow doctors to visualize the colon and rectum and identify the presence and number of polyps.
In summary, genetic testing for APC gene mutations is the gold standard for confirming a diagnosis of Gardner's syndrome, especially when combined with clinical findings and family history.
