Confirmed germline pathogenic / likely-pathogenic variant in CDKN2A (p16/INK4a) — gene-sp...

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

ID	`RF-CDKN2A-SPECIFIC-PDAC-CARRIER`
Type	Red flag
Status	reviewed 2026-05-20 \| pending_clinical_signoff
Diseases	`DIS-MELANOMA` `DIS-PDAC`
Sources	`SRC-CANTO-CAPS-2018` `SRC-CAPS-CONSORTIUM-PANCREATIC-2020` `SRC-NCCN-GENETIC-FAMILIAL-BREAST-OVARIAN-2025`

Red Flag Origin

Definition	Confirmed germline pathogenic / likely-pathogenic variant in CDKN2A (p16/INK4a) — gene-specific variant of the broader Familial Atypical Multiple Mole Melanoma (FAMMM) phenotype. Distinguishing clinical feature: pancreatic ductal adenocarcinoma (PDAC) signal — lifetime PDAC risk ~17% in p16-Leiden cohort (Netherlands founder variant), up to ~58% in some CDKN2A-3′-UTR variant families. Melanoma signal also present (~70-80% lifetime), often multiple primary melanomas + atypical mole syndrome. Some families show pleomorphic glial brain tumors. Distinct from existing RF-FAMMM-CONFIRMED-CARRIER which covers broader FAMMM phenotype without specific PDAC routing — this RF anchors the gene-specific multi-organ surveillance pathway including pancreatic surveillance per CAPS Consortium criteria. Patient has confirmed positive germline test; no current personal cancer diagnosis in the carrier bein...
Clinical direction	investigate
Category	other

Trigger Logic

{
  "any_of": [
    {
      "finding": "cdkn2a_p16_leiden_confirmed",
      "value": true
    },
    {
      "finding": "cdkn2a_with_pdac_family_history",
      "value": true
    }
  ],
  "type": "lab_value"
}

Notes

Prevention-persona RedFlag for CDKN2A-specific carriers (gene-specific RF vs the broader FAMMM RF). Pancreatic surveillance per CAPS Consortium 2018/2020: alternating EUS + abdominal MRI/MRCP every 12 months from age 40 OR 10 years before earliest PDAC in family (whichever earlier). Melanoma surveillance: annual full-body skin examination + dermoscopy from age 10-12; mapping photography for multiple atypical moles. Patient should know aggressive sun protection + lifelong CDKN2A-specific cohort. STUB pending two-Co- Lead signoff per CHARTER §6.1 dev-mode.

Used By

Indications

IND-CDKN2A-PDAC-CARRIER-OBSERVATION - IND-CDKN2A-PDAC-CARRIER-OBSERVATION
IND-CDKN2A-PDAC-CARRIER-SURVEILLANCE - IND-CDKN2A-PDAC-CARRIER-SURVEILLANCE