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IEMbase 0113: CPOX-related coproporphyrinogen oxidase deficiency

Scope

Field Value
IEMbase ID 113
Nosology 17.1.07.01
Gene CPOX
External IDs OMIM:121300; ORPHA:79273
Generated mapping MAPPED, high confidence
Candidate DisMech targets Inherited_Porphyria.yaml#Hereditary Coproporphyria
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents this as CPOX-related coproporphyrinogen oxidase deficiency, with alternate labels hereditary coproporphyria and HC. Treatability is marked yes, but the cached JSON has no treatment rows.

The characteristic biochemical rows are increased urinary delta-ALA, increased stool coproporphyrin III, increased urinary porphobilinogen, and markedly increased total urinary porphyrins in adolescence and adulthood. Clinical rows include psychotic behavior, blisters, red-brown fluorescent urine, coma, constipation, depression, hyperesthesia, hypertension, motor neuropathy, nausea, renal failure, seizures, tachycardia, and vomiting.

DisMech phenotype coverage

Inherited_Porphyria.yaml includes a hereditary coproporphyria subtype anchored to CPOX loss of function. The umbrella entry covers the shared acute hepatic porphyria pattern: attacks with abdominal pain, vomiting, weakness, neuropathy, urinary ALA and porphobilinogen, and cutaneous photosensitivity for the cutaneous/overlap porphyrias.

The treatment section applies group-level acute hepatic porphyria management, including trigger avoidance/supportive care, hemin or heme arginate, and givosiran, but it is not tailored specifically to HCP.

Concordance and completeness

Judgement: correct subtype-level mapping with incomplete HCP-specific granularity.

The mapping is concordant for CPOX/HCP and for the acute hepatic porphyria attack phenotype. DisMech provides a good mechanism scaffold and shared treatment rationale. IEMbase is more specific for HCP biochemical discrimination, especially stool coproporphyrin III, and it enumerates several attack features not specifically called out for the subtype: blisters, fluorescent urine, coma, hyperesthesia, renal failure, and depressive or psychotic symptoms.

Curation actions

  • Keep the current target as Inherited_Porphyria.yaml#Hereditary Coproporphyria.
  • Consider HCP-specific biochemical rows for stool coproporphyrin III and urinary total porphyrins.
  • Review whether HCP should remain a subtype only or eventually get a standalone entry if subtype-specific phenotype/treatment evidence is expanded.