Ethylmalonic encephalopathy (WP5030)

Homo sapiens

Cysteine is converted into pyruvate and hydrogen sulfide (H2S) through desulphuration and deamination. Then, H2S is oxidised by SQR, after which ETHE1 takes care of converting into sulfite (SO3 2-). One disorder named Ethylmalonic encephalopathy (EE) is linked to this pathway, a rare mitochondrial disease caused by variants within the ETHE1 gene. This pathway was inspired by Chapter 9 (edition 4) of the book of Blau (ISBN 3642403360 (978-3642403361)).


Denise Slenter , Andra Waagmeester , Egon Willighagen , Eric Weitz , Finterly Hu , and Friederike Ehrhart


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Homo sapiens


Inherited Metabolic Disorders (IMD) Pathways Rare Diseases


Disease Ontology

ethylmalonic encephalopathy

Pathway Ontology

ethylmalonic encephalopathy pathway


Label Type Compact URI Comment
Cysteine Metabolite chebi:15356
Electron Metabolite chebi:10545
H2S Metabolite chebi:16136
CoEnzyme Q Metabolite chebi:46245
SO3 2-(sulfite) Metabolite chebi:17359
R-SSH, example:S-sulfanylglutathione Metabolite chebi:58905
Pyruvate Metabolite chebi:32816
O2 Metabolite chebi:15379
R, example:glutathione Metabolite chebi:57925
SO4 2-(sulfate) Metabolite chebi:16189
S2O3 2-(thiosulfate) Metabolite chebi:16094
2 H2O Metabolite chebi:15377
Rhodanese Protein uniprot:Q16762
ETHE1 Protein uniprot:O95571
SQR Protein eccode:
SOX Protein uniprot:P51687 aka Sulfite Oxidase


  1. Physician’s Guide to the Diagnosis, Treatment, and Follow-Up of Inherited Metabolic Diseases [Internet]. Blau N, Duran M, Gibson KM, Dionisi-Vici C. Springer; 2014. 0 p. Available from: OpenLibrary Worldcat
  2. Multiple sources of metabolic disturbance in ETHE1-related ethylmalonic encephalopathy. Barth M, Ottolenghi C, Hubert L, Chrétien D, Serre V, Gobin S, et al. J Inherit Metab Dis. 2010 Dec;33 Suppl 3:S443-53. PubMed Europe PMC Scholia
  3. Coenzyme Q deficiency causes impairment of the sulfide oxidation pathway. Ziosi M, Di Meo I, Kleiner G, Gao XH, Barca E, Sanchez-Quintero MJ, et al. EMBO Mol Med. 2017 Jan;9(1):96–111. PubMed Europe PMC Scholia