IEMbase 0109: PPOX-related protoporphyrinogen oxidase deficiency
Scope
| Field | Value |
|---|---|
| IEMbase ID | 109 |
| Nosology | 17.1.09.01 |
| Gene | PPOX |
| External IDs | OMIM:176200 |
| Generated mapping | UNMAPPED |
| Candidate DisMech targets | Inherited_Porphyria.yaml#Variegate Porphyria |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents this as PPOX-related protoporphyrinogen oxidase deficiency, with alternate labels porphyria variegata, South African porphyria, and PV. Treatability is marked yes, but the cached JSON has no treatment rows.
The biochemical rows are increased urinary delta-ALA, increased stool coproporphyrin III, increased urinary porphobilinogen, increased urinary total porphyrins, increased stool protoporphyrin, low-to-normal plasma magnesium, and decreased plasma sodium.
Clinical rows include psychotic behavior, blisters, coma, constipation, hepatopathy, hyperesthesia, hypertension, hepatocellular carcinoma or hepatoblastoma, motor neuropathy, nausea, renal failure, seizures, tachycardia, and vomiting.
DisMech phenotype coverage
The generated UNMAPPED status is a false negative. Inherited_Porphyria.yaml
has a Variegate Porphyria subtype with PPOX loss-of-function variants,
autosomal dominant acute hepatic porphyria context, neurovisceral attack
susceptibility, cutaneous photosensitivity, and shared acute hepatic porphyria
biomarkers including urinary ALA and porphobilinogen.
The local entry covers acute hepatic porphyria features such as abdominal pain, vomiting, peripheral neuropathy, and cutaneous photosensitivity at group/subtype level. It also includes hemin and givosiran treatment context for acute hepatic porphyrias, though not a variegate-porphyria-specific treatment section.
Concordance and completeness
Judgement: false negative to existing subtype-level local coverage.
DisMech is stronger for pathway mechanism, PPOX gene anchoring, acute hepatic porphyria modeling, and group-level treatment rationale. IEMbase is more granular for variegate-porphyria-specific biochemical compartments and clinical attack details, including stool coproporphyrin III/protoporphyrin, low sodium, autonomic cardiovascular rows, neuropsychiatric rows, renal failure, and hepatopathy/tumor rows.
Curation actions
- Resolve to
Inherited_Porphyria.yaml#Variegate Porphyriaas the current canonical target. - Consider a future standalone variegate porphyria entry if porphyria subtype curation is split from the umbrella.
- Review IEMbase-specific VP biomarkers and acute-attack phenotypes for future expansion, especially stool porphyrin pattern and hyponatremia/renal involvement.