Confirmed germline pathogenic / likely-pathogenic variant in SDHA (succinate dehydrogenas...

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

ID	`RF-SDHA-SPECIFIC-CARRIER`
Type	Red flag
Status	reviewed 2026-05-20 \| pending_clinical_signoff
Diseases	`DIS-PHEOCHROMOCYTOMA`
Sources	`SRC-ENDOCRINE-SOCIETY-MEN-2023` `SRC-NCCN-GENETIC-FAMILIAL-BREAST-OVARIAN-2025` `SRC-NCCN-NET-2025`

Red Flag Origin

Definition	Confirmed germline pathogenic / likely-pathogenic variant in SDHA (succinate dehydrogenase complex subunit A) — paraganglioma syndrome type 5 (PGL5). SDHA is the newer-recognized SDHx gene with lower and later-onset penetrance than SDHB / SDHD: lifetime risk of pheochromocytoma + paraganglioma is approximately 10-20% by age 70, with most events emerging in adulthood (median 30s-50s) rather than pediatric onset. Tumor spectrum also includes SDH-deficient gastrointestinal stromal tumor (SDH-deficient GIST — wild-type c-KIT and PDGFRA, indolent multifocal biology, imatinib-non-responsive), occasional clear-cell / type-2-papillary renal cell carcinoma, and rare pituitary adenoma reports in the broader "3PAs" association. Inheritance is autosomal-dominant without the SDHD / SDHAF2 maternal- imprinting pattern (penetrant from either parent). Patient has had germline SDHA testing returned posi...
Clinical direction	investigate
Category	other

Trigger Logic

{
  "any_of": [
    {
      "finding": "germline_sdha_specific_carrier",
      "value": true
    },
    {
      "finding": "paraganglioma_pgl5_clinical_criteria_met",
      "value": true
    }
  ],
  "type": "lab_value"
}

Notes

Gene-specific paraganglioma syndrome 5 (PGL5) confirmed-carrier RF. Fires on documented germline SDHA pathogenic / likely-pathogenic variant positivity in an asymptomatic individual. Distinct from the multi-gene RF-SDH-CONFIRMED-CARRIER which fires on the legacy per- gene `germline_sdha_pathogenic_variant_confirmed` finding; this RF uses `germline_sdha_specific_carrier` to avoid double-firing on patients whose pedigree-specific variant is being tracked under the new gene-stratified surveillance pathway. Engine routes to PreventionPlan recommending: (a) IND-SDHA-CARRIER-SURVEILLANCE (standard) — biennial whole-body MRI from age 18-20 (no pediatric whole-body MRI given adulthood-onset profile); annual plasma free metanephrines + methoxytyramine (3-MT preferred — SDHx-associated PGLs frequently dopaminergic); head + neck MRI q3y for parasympathetic screening; abdominal MRI q2y for SDH-deficient GIST + RCC; cascade testing offered to first-degree relatives. (b) IND-SDHA-CARRIER-SYMPTOM-DRIVEN (aggressive in the rhetorical sense — actually represents a less-intensive symptom-driven approach offered as the alternative to scheduled imaging given SDHA's lower penetrance; the patient-share...

Used By

Indications

IND-SDHA-CARRIER-SURVEILLANCE - IND-SDHA-CARRIER-SURVEILLANCE
IND-SDHA-CARRIER-SYMPTOM-DRIVEN - IND-SDHA-CARRIER-SYMPTOM-DRIVEN