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IEMbase 0177: MLYCD-related malonic aciduria

Scope

Field Value
IEMbase ID 177
Nosology 1.2.23.01
Gene MLYCD
External IDs OMIM:248360; ORPHA:943
Generated mapping MAPPED to Migraine_with_Aura.yaml by alias MA
Candidate DisMech targets None valid
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents this as MLYCD-related malonyl-CoA decarboxylase deficiency, with alternate labels malonic aciduria and MA. Treatability is marked unknown, and there are no treatment rows in the extracted JSON.

The biochemical rows include increased C3-DC malonylcarnitine, increased urine C4-DC methylmalonylcarnitine, decreased to normal free carnitine, decreased malonyl-CoA decarboxylase activity, normal to increased plasma and urinary ketones, increased urinary malonic acid as the characteristic organic acid, increased to markedly increased malonic acid with additional urinary organic-acid abnormalities including 3-hydroxybutyric, adipic, ethylmalonic, fumaric, glutaric, malic, methylmalonic, sebacic, suberic, and succinic acids, decreased urine methylmalonic-acid/malonic-acid ratio, normal to increased ammonia, variable base excess, low to normal cholesterol, low to normal glucose, and normal to increased lactate. Clinical rows include basal ganglia lesions, cerebellar white matter abnormalities, dystonia, infection-triggered acute encephalopathy, epilepsy, frontotemporal atrophy, hepatomegaly, hypoglycemia, axial hypotonia, metabolic acidosis, neonatal seizures, cardiomyopathy, developmental delay, and vomiting.

DisMech phenotype coverage

No valid local DisMech target was found. The generated mapping to Migraine_with_Aura.yaml is a false positive caused by the short alias MA. The local migraine entry models cortical spreading depolarization, aura, and headache biology; it has no MLYCD, malonyl-CoA decarboxylase activity, malonic aciduria, malonylcarnitine, metabolic acidosis, cardiomyopathy, or developmental encephalopathy coverage.

Local search found Combined_Malonic_and_Methylmalonic_Aciduria.yaml, but that entry models ACSF3-related CMAMMA, not MLYCD-related isolated malonic aciduria.

Concordance and completeness

Judgement: generated mapping is false; this is a true local gap.

IEMbase points to a distinct monogenic malonic aciduria with neurologic, cardiac, and metabolic decompensation features. The alias MA is too broad to support automated exact matching.

Curation actions

  • Do not map this record to Migraine_with_Aura.yaml.
  • Add a future MLYCD/malonyl-CoA decarboxylase deficiency entry.
  • Treat MA as an unsafe short alias in mapping.
  • Expected future coverage: MLYCD, reduced malonyl-CoA decarboxylase activity, malonic aciduria, malonylcarnitine, low methylmalonic-acid/malonic-acid ratio, cardiomyopathy, developmental delay, epilepsy/seizures, basal ganglia and white matter changes, metabolic acidosis, hypoglycemia, hepatomegaly, and infection-triggered encephalopathy.