Table 1.
Summary of clinical recommendations for APC I1307K variant carriers
| Organization | Variant Classification | Screening Recommendations | Additional Notes |
|---|---|---|---|
| National Comprehensive Cancer Network (NCCN)a | Significant risk factor for CRC in average-risk Ashkenazi Jews | High-quality colonoscopy every 5 years, starting at age 40 or 10 years prior to CRC diagnosis in a first-degree relative. | Applies to all carriers, regardless of ancestry, due to insufficient evidence to support ancestry-specific risk differences. Acknowledges that some individuals may be unaware of their Ashkenazi heritage. |
| International Society for Gastrointestinal Hereditary Tumours (InSiGHT) [25] | Pathogenic with low penetrance, specifically in Ashkenazi Jewish populations | Colonoscopy every 5 years, starting at age 45–50 for carriers of Ashkenazi descent. Non-Ashkenazi carriers should follow national CRC screening guidelines. | Differentiates recommendations based on ancestry, with additional surveillance limited to Ashkenazi carriers. |
| UK Cancer Genetics Group (UKCGG) [26] | Does not recommend considering or reporting the variant in NHS-funded diagnostic APC testing | Additional surveillance only in the presence of a strong family history of CRC |