Confirmed germline pathogenic / likely-pathogenic variant in CDH1 (E-cadherin) — Heredita...

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

ID	`RF-HDGC-CDH1-CONFIRMED-CARRIER`
Type	Red flag
Status	reviewed 2026-05-19 \| pending_clinical_signoff
Diseases	`DIS-BREAST` `DIS-GASTRIC`
Sources	`SRC-ESMO-GASTRIC-2024` `SRC-NCCN-BREAST-2025` `SRC-NCCN-GENETIC-FAMILIAL-BREAST-OVARIAN-2025`

Red Flag Origin

Definition	Confirmed germline pathogenic / likely-pathogenic variant in CDH1 (E-cadherin) — Hereditary Diffuse Gastric Cancer (HDGC) syndrome. Autosomal-dominant; highly penetrant. Lifetime diffuse-type (signet ring cell) gastric cancer risk ~37-42% by age 80 in females, ~33-37% in males (downward-revised from earlier ~70-80% estimates per IGCLC 2020 + Hansford 2015). Lifetime invasive lobular breast cancer risk in female carriers ~37-55% by age 80 (lobular histology dominant; ductal less). Other low-frequency cancers reported: cleft lip/palate (developmental), signet-ring colon (rare). Linitis plastica presentation common when symptomatic. Patient has confirmed positive germline test; no current personal cancer diagnosis in the carrier being assessed. Prevention-persona RedFlag (§20, v0.3 pediatric predisposition expansion — though HDGC carriers are typically adults not children; included in pedi...
Clinical direction	investigate
Category	other

Trigger Logic

{
  "any_of": [
    {
      "finding": "germline_cdh1_pathogenic_variant_confirmed",
      "value": true
    },
    {
      "finding": "germline_cdh1_likely_pathogenic_variant",
      "value": true
    },
    {
      "finding": "hdgc_igclc_clinical_criteria_met",
      "value": true
    }
  ],
  "type": "lab_value"
}

Notes

Prevention-persona RedFlag for CDH1 / HDGC confirmed carriers per IGCLC 2020 international guideline. Prophylactic total gastrectomy (PTG) recommended ages 20-30 (range 18-40 per individualised discussion); endoscopic surveillance is acknowledged inferior to PTG (diffuse-type signet-ring cell foci poorly visible) but offered to PTG-declining carriers. Female carriers: BRCA-style breast surveillance from age 30. STUB pending two-Co-Lead signoff per CHARTER §6.1 dev-mode.

Used By

Indications

IND-HDGC-CDH1-CARRIER-PREVENTION-OBSERVATION - IND-HDGC-CDH1-CARRIER-PREVENTION-OBSERVATION
IND-HDGC-CDH1-CARRIER-PREVENTION-SURVEILLANCE - IND-HDGC-CDH1-CARRIER-PREVENTION-SURVEILLANCE