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IEMbase 0107: FECH-related ferrochelatase deficiency

Scope

Field Value
IEMbase ID 107
Nosology 17.1.1.01
Gene FECH
External IDs OMIM:177000
Generated mapping MAPPED
Candidate DisMech targets Inherited_Porphyria.yaml#Erythropoietic Protoporphyria
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents this as FECH-related ferrochelatase deficiency, with alternate label erythropoietic protoporphyria (EPP). Treatability is marked yes, but the cached JSON has no treatment rows.

The characteristic biochemical rows are normal-to-increased stool protoporphyrin, increased free erythrocyte protoporphyrin, and low-to-normal serum ferritin and iron. Clinical rows are anemia, liver dysfunction, and microcytosis.

DisMech phenotype coverage

The generated mapping to Inherited_Porphyria.yaml#Erythropoietic Protoporphyria is correct at the current local modeling level. The inherited-porphyria umbrella has an erythropoietic protoporphyria subtype and a protoporphyria mechanism branch covering reduced FECH expression, protoporphyrin IX accumulation, cutaneous phototoxicity, and liver dysfunction risk.

DisMech also includes increased erythrocyte or plasma protoporphyrin as a biochemical readout and afamelanotide pharmacotherapy for EPP/X-linked protoporphyria light tolerance.

Concordance and completeness

Judgement: correct subtype-level mapping with good mechanism concordance.

DisMech is richer for the defining phototoxicity mechanism and EPP/XLP treatment context. IEMbase is more granular for the FECH-specific lab profile, especially free RBC protoporphyrin, stool protoporphyrin, low/low-normal iron and ferritin, microcytosis, and anemia. DisMech currently records anemia primarily under congenital erythropoietic porphyria rather than FECH-related EPP.

Curation actions

  • Keep Inherited_Porphyria.yaml#Erythropoietic Protoporphyria as the current target.
  • Consider a future standalone EPP entry if porphyria subtypes are split out of the umbrella.
  • Review iron/ferritin, microcytosis, and anemia as possible FECH-EPP phenotype or biomarker additions before curating them locally.