Lynch Syndrome

Lynch syndrome causes

Lynch syndrome is caused by inherited mutations in specific DNA mismatch repair (MMR) genes, including:

• MLH1, MSH2, MSH6, PMS2, or a deletion in EPCAM
• These genes normally fix errors that happen when cells divide and copy DNA
• Mutations allow these errors to accumulate, which may lead to cancer

Lynch syndrome risk factors

• Family history of Lynch-associated cancers (e.g., colorectal, endometrial, ovarian)
• Cancer diagnosis in relatives under age 50
• Personal history of more than one Lynch-associated cancer
• Ashkenazi Jewish ancestry

Lynch syndrome symptoms

Lynch syndrome itself does not cause symptoms, but associated cancers may cause:

• Rectal bleeding, changes in bowel habits
• Unusual vaginal bleeding
• Abdominal or pelvic pain
• Unexplained weight loss or fatigue

Lynch syndrome diagnosis

Diagnosing Lynch syndrome often includes:

• Reviewing personal and family cancer history
• Tumor testing such as:
  – Microsatellite instability (MSI) testing
  – Immunohistochemistry (IHC)
• Genetic counseling and blood-based genetic testing for MMR gene mutations

Lynch syndrome treatment

While there is no cure for Lynch syndrome, treatment focuses on reducing cancer risk and detecting cancer early:

• Frequent colonoscopies beginning at a younger age
• Routine screenings for other cancers (endometrial, ovarian, stomach, etc.)
• Preventive surgeries, such as hysterectomy, for those at high risk
• Possible use of aspirin therapy to lower colorectal cancer risk
• Standard cancer treatments (surgery, chemo, immunotherapy) if cancer develops

When to seek care

Talk to your doctor if you:

• Have a personal or family history of early or multiple cancers
• Experience unusual bleeding, ongoing digestive issues, or unexplained weight loss
• Are considering genetic testing or want to learn more about your cancer risk
• Need guidance on cancer screenings based on family history