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IEMbase 0420: POLG-related spinocerebellar ataxia with epilepsy, included

Scope

Field Value
IEMbase ID 420
Nosology 9.2.01.02
Gene POLG
External IDs OMIM:607459; ORPHA:402082; ORPHA:70595; ORPHA:254881
Generated mapping MAPPED; Sensory_Ataxic_Neuropathy_Dysarthria_Ophthalmoparesis.yaml
Candidate DisMech targets Sensory_Ataxic_Neuropathy_Dysarthria_Ophthalmoparesis.yaml
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents a POLG ataxia-neuropathy spectrum record with alternate name sensory ataxic neuropathy, dysarthria, and ophthalmoparesis (SANDO). It records autosomal dominant inheritance in the source row. Clinical rows include adult axonal sensory ataxic neuropathy, dysarthria, ophthalmoparesis/ophthalmoplegia, muscle mtDNA depletion, epileptic seizures, cognitive impairment, headache, and migraine. There are no treatment rows.

DisMech phenotype coverage

The generated mapping is correct. Local Sensory_Ataxic_Neuropathy_Dysarthria_Ophthalmoparesis.yaml directly models SANDO as a POLG-related mitochondrial DNA maintenance disorder with mtDNA depletion and multiple deletions, respiratory-chain deficiency in post-mitotic tissues, sensory ataxic neuropathy, dysarthria, ophthalmoparesis/progressive external ophthalmoplegia, myopathy, ragged-red/COX-negative muscle pathology, and seizure risk within the broader POLG spectrum.

Local DisMech is stronger for mechanism and for management cautions, including avoidance of valproate in POLG-related disorders. IEMbase adds migraine, headache, cognitive impairment, and explicit muscle mtDNA depletion prompts.

Concordance and completeness

Judgement: correct high-concordance mapping to Sensory_Ataxic_Neuropathy_Dysarthria_Ophthalmoparesis.yaml.

The disease name, SANDO synonym, POLG gene, mtDNA-maintenance mechanism, sensory ataxic neuropathy, dysarthria, ophthalmoparesis/ophthalmoplegia, and epilepsy context align well.

Curation actions

  • Retain the mapping to Sensory_Ataxic_Neuropathy_Dysarthria_Ophthalmoparesis.yaml.
  • Consider reviewing the inheritance row because local DisMech models SANDO as typically autosomal recessive, while IEMbase lists autosomal dominant.
  • Consider adding IEMbase's headache, migraine, cognitive impairment, and muscle mtDNA-depletion prompts after source verification.