Lynch Syndrome with Family History and No Personal History of Colorectal or Other Cancer
Individuals with a family history suggestive of Lynch syndrome but no personal history of colorectal or another cancer — and no known causative mutation identified in the family — represent a distinct clinical scenario requiring structured risk assessment before any intervention.
Clinical Scenario
No personal history of colorectal or another Lynch-associated cancer; family history that raises concern for Lynch syndrome; no previously identified Lynch syndrome germline mutation in the family. In this setting, risk prediction models should be offered as a first step to estimate the probability of a hereditary mismatch repair defect.
Approach (Partial Overview)
When risk assessment places the individual above an appropriate probability threshold, a targeted form of germline genetic testing is indicated — though the full testing pathway, which genes are prioritised, and the sequencing of steps require the complete structured protocol.
Full gene panel details, sequencing strategy, and clinical decision thresholds are available in the evidence-based regimen.
References
DOI: 10.1053/j.gastro.2015.07.036
- In patients without a personal history of colorectal or another cancer but with a family history suggestive of Lynch syndrome, the AGA suggests that risk prediction models be offered rather than doing nothing.
- If the probability is above the threshold, then germline genetic testing for mutations in MLH1, MSH2, MSH6, and PMS2 should be offered.
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