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IEMbase 0745: CYC1-related mitochondrial cytochrome c1 deficiency

Scope

Field Value
IEMbase ID 745
Nosology 7.3.02.03
Nosology code IEM0488
Gene CYC1
External IDs OMIM:615453; ORPHA:1460
Generated mapping CANDIDATE; fuzzy COX4I1-Related_COX_Deficiency.yaml
Candidate DisMech targets No exact CYC1 / mitochondrial complex III nuclear type 6 target identified
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents autosomal recessive CYC1-related mitochondrial cytochrome c1 deficiency, also labeled mitochondrial complex III deficiency, nuclear type 6. The cached rows include normal-to-high ammonia in infancy and childhood, plasma lactate elevation in infancy and childhood, possible episodic encephalopathy, possible failure to thrive, crisis hyperammonemia, insulin- treatment hyperglycemia, lactic acidosis from infancy through adulthood, possible childhood liver failure, and seizures across infancy to adolescence.

DisMech phenotype coverage

No exact CYC1 target was identified locally.

The generated COX4I1-Related_COX_Deficiency.yaml candidate is a false positive. COX4I1 is a complex IV nuclear structural-subunit disease; CYC1 encodes cytochrome c1 of complex III. The shared mitochondrial/lactate context does not constitute exact coverage.

Concordance and completeness

Judgement: true CYC1 complex III local gap. Reject the COX4I1 candidate as exact coverage.

IEMbase provides a focused curation seed for a CYC1 entry: lactate, hyperammonemia during crises, lactic acidosis, episodic encephalopathy, seizures, liver failure, failure to thrive, and insulin-treated hyperglycemia. DisMech lacks a CYC1/MC3DN6 disease identity and mechanism.

Curation actions

  • Add CYC1-related mitochondrial complex III deficiency, nuclear type 6, to the complex III backlog.
  • Reject COX4I1-Related_COX_Deficiency.yaml as exact coverage.
  • Preserve lactate, hyperammonemia, lactic acidosis, episodic encephalopathy, seizures, liver-failure, FTT, and hyperglycemia prompts.