APC I1307K — modestly elevated colorectal cancer risk
One copy of the APC I1307K variant detected.
You have one copy of the APC I1307K gene change, which modestly raises colorectal cancer risk.
Associated with a modestly elevated lifetime risk of colorectal cancer (roughly 1.5–2× the baseline). Earlier and more frequent colonoscopy screening is generally recommended.
Your lifetime risk of colorectal cancer is roughly 1.5–2× the average. Starting colonoscopy screening earlier and more often is generally recommended.
What this means
APC I1307K creates a small stretch of DNA that is more prone to a specific mutation during cell division. Unlike the classical APC mutations that cause familial adenomatous polyposis, this variant produces a much smaller effect — a modest lifetime increase in colorectal cancer risk rather than near-certainty. Most professional guidelines recommend starting colonoscopy screening earlier and at shorter intervals for carriers.
This change creates a small stretch of DNA in the APC gene that's more likely to pick up a second, cancer-driving mutation when your cells divide. It's a different beast from the classical APC changes that cause near-certain colorectal cancer — the effect here is much smaller, a modest bump in lifetime risk rather than a near-inevitability. Most guidelines suggest starting colonoscopy earlier and repeating it more often if you have this change, which catches polyps before they turn into cancer.
Caveats
- The risk increase is moderate, not extreme. Most carriers never develop colorectal cancer.
- This is distinct from classical APC mutations causing familial adenomatous polyposis.
- Screening guidance varies between countries and societies; consult a GP or gastroenterologist.
Populations
- Common in Ashkenazi Jewish populations (~6% carrier frequency); rare elsewhere