A first-degree relative of the patient (parent, sibling, or child) has a documented posit...

Deterministic view of the source YAML entity. Clinical authority remains with the cited source IDs and reviewer sign-off state.

ID	`RF-CASCADE-LYNCH-FDR-POSITIVE`
Type	Red flag
Status	reviewed 2026-05-19 \| pending_clinical_signoff
Diseases	`DIS-CRC` `DIS-ENDOMETRIAL` `DIS-GASTRIC` `DIS-OVARIAN` `DIS-PDAC` `DIS-PROSTATE` `DIS-UROTHELIAL`
Sources	`SRC-ASCO-ACMG-LYNCH-2014` `SRC-ESMO-CRC-2024` `SRC-NCCN-GENETIC-FAMILIAL-CRC-2025`

Red Flag Origin

Definition	A first-degree relative of the patient (parent, sibling, or child) has a documented positive germline test result for a Lynch syndrome (MMR / EPCAM) gene — MLH1, MSH2, MSH6, PMS2, or EPCAM (3' deletion silencing MSH2). The patient themself has NOT yet been germline-tested and has no current personal cancer diagnosis. Per autosomal-dominant inheritance, the patient carries a 50% prior probability of also being a Lynch carrier — substantially higher than the ~15-25% positive yield of pedigree-suspicion testing — providing strong clinical motivation for cascade germline testing. Distinct from RF-LYNCH-FAMILY-HISTORY-SUSPICION (fires on phenotype / pedigree pattern alone, before any relative has tested positive) and from RF-LYNCH-CONFIRMED-CARRIER (fires after the patient's own positive germline test). Prevention-persona RedFlag (§20, v0.2-B cascade-testing pilot 2026-05-19).
Clinical direction	investigate
Category	other

Trigger Logic

{
  "any_of": [
    {
      "finding": "family_first_degree_relative_lynch_carrier_confirmed",
      "value": true
    }
  ],
  "type": "lab_value"
}

Notes

v0.2-B cascade-testing pilot (2026-05-19). Fires when a first-degree relative (FDR — parent, sibling, child) of an asymptomatic patient has a confirmed positive germline test for an MMR / EPCAM gene. Engine routes to PreventionPlan recommending: (a) IND-CASCADE-LYNCH-FDR-POSITIVE-TESTING (standard) — cascade germline MMR / EPCAM panel testing for the patient + pre/ post-test genetic counseling. The known familial variant anchors site-specific (single-variant) testing as the most efficient first-line option, with expansion to full-gene sequencing if site-specific is negative and high suspicion persists. (b) IND-CASCADE-LYNCH-FDR-POSITIVE-SURVEILLANCE (alternative) — empirical enhanced surveillance per the carrier protocol for patients who decline cascade germline testing for any reason (cost, insurance, psychological, family privacy). **50% prior probability** in autosomal-dominant inheritance (one parent heterozygous) is the cornerstone of cascade-testing cost-effectiveness — vastly outperforms pedigree-suspicion populations (~15-25% positive yield) and supports the strong recommendation to test rather than rely on phenotype. STUB pending two-Clinical-Co-Lead signoff per CHARTER §...

Used By

Indications

IND-CASCADE-LYNCH-FDR-POSITIVE-SURVEILLANCE - IND-CASCADE-LYNCH-FDR-POSITIVE-SURVEILLANCE
IND-CASCADE-LYNCH-FDR-POSITIVE-TESTING - IND-CASCADE-LYNCH-FDR-POSITIVE-TESTING