Cancer Risks and Management per National Comprehensive Cancer Network (NCCN) Genetic/Familial High-Risk Assessment: Colorectal Version 1.2020
Men & women with two mutations in MUTYH:
Colon cancer risk: High risk – Recommend colonoscopy every 1-2 years beginning at age 25-30; colectomy considered based on polyp burden and age.
Duodenal cancer risk: Elevated – Consider baseline upper endoscopy beginning at age 30-35 and repeat based on findings. Recommend annual physical exam.
Men & women with one mutation in MUTYH:
Cancer risks: Not well established – having only one mutation in 𝘔𝘜𝘛𝘠𝘏 should not impact medical management. Cancer screening and management should be based on personal and family history.
Inheritance: Autosomal recessive; thus, individuals have 𝘔𝘜𝘛𝘠𝘏-associated polyposis (also known as MAP) syndrome only if they have mutations in both copies of their 𝘔𝘜𝘛𝘠𝘏 gene. If both parents have a 𝘔𝘜𝘛𝘠𝘏 mutation, each of their children have a 25% risk of inheriting both 𝘔𝘜𝘛𝘠𝘏 mutations (meaning one from each parent), leading to MAP.
Family Testing: At-risk family members should consider genetic counseling and testing.
Reproductive Considerations: Option for preimplantation genetic diagnosis (PGD) may be available to ensure future generations do not inherit the known gene mutation. PGD is a procedure available for certain gene mutations to screen the embryo prior to pregnancy.
Check out the full guidelines by creating a FREE account at : https://www.nccn.org/professionals/physician_gls/pdf/genetics_colon.pdf