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IEMbase 0451: SDHA-related succinate dehydrogenase subunit A deficiency

Scope

Field Value
IEMbase ID 451
Nosology 7.2.01.01
Gene SDHA
External IDs OMIM:252011; ORPHA:44890
Generated mapping UNMAPPED; low candidate Pyruvate_Dehydrogenase_Deficiency.yaml / E1-beta deficiency
Candidate DisMech targets No exact local target
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents SDHA-related succinate dehydrogenase subunit A deficiency, also called mitochondrial complex II deficiency. It records autosomal recessive inheritance. Biochemical rows include decreased complex II activity in fibroblasts and increased lactate. Clinical rows include Leigh syndrome, Kearns-Sayre syndrome, hypertrophic cardiomyopathy, dementia, encephalopathy, myopathy, and short stature. There are no treatment rows.

DisMech phenotype coverage

There is no exact local DisMech target for AR SDHA mitochondrial complex II deficiency. Local SDHA context exists in Pheochromocytoma_Paraganglioma.yaml as part of SDHx cancer predisposition, but that is not the metabolic complex II deficiency entity. Leigh_Syndrome.yaml provides broad phenotype context for Leigh syndrome and oxidative phosphorylation disease, but it does not name SDHA or provide an SDHA/complex II subtype.

The generated Pyruvate_Dehydrogenase_Deficiency.yaml E1-beta candidate is a false positive. Local PDH deficiency involves PDHA1, PDHB, PDHX, DLD, PDP1, or related pyruvate dehydrogenase complex biology, not succinate dehydrogenase complex II deficiency.

Concordance and completeness

Judgement: true SDHA/complex II deficiency local gap; reject pyruvate dehydrogenase E1-beta deficiency as an exact mapping.

The candidate shares lactic acidosis and neurologic mitochondrial disease vocabulary, but the enzyme complex, gene, proximal biochemical lesion, and expected modeling target are different.

Curation actions

  • Keep this record unmapped until an SDHA-related mitochondrial complex II deficiency target exists, or until an explicit Leigh-syndrome subtype decision includes SDHA.
  • Do not map to Pyruvate_Dehydrogenase_Deficiency.yaml.
  • Do not map metabolic SDHA deficiency to SDHx cancer-predisposition coverage.
  • If curated, include SDHA, autosomal recessive inheritance, succinate dehydrogenase complex II deficiency, decreased fibroblast complex II activity, lactate elevation, Leigh syndrome, cardiomyopathy, encephalopathy, myopathy, dementia, short stature, and Kearns-Sayre-like presentation only if source evidence supports that row.