Reactome: A Curated Pathway Database

Defective MTRR causes methylmalonic aciduria and homocystinuria type cblE (R-HSA-3359467)

Species Homo sapiens


Defects in MTRR cause methylcobalamin deficiency type E (cblE; methionine synthase reductase deficiency; MIM:236270) (Wilson et al. 1999). Patients with cblE exhibit megaloblastic anemia and hyperhomocysteinemia. SAM is used as a methyl donor in many biological reactions and demethylation of SAM produces S-adenosylhomocysteine, which is deadenosylated to form homocysteine. Homocysteine remethylation is carried out by MTR, which requires MTRR to maintain enzyme-bound cobalamin (Cbl) in its active form; but in cblE patients, MTR becomes inactivated and thus homocysteine accumulates.

Locations in the PathwayBrowser
Cross References
Database Identifier
BioModels Database BIOMD0000000268
Name Identifier Synonyms
methylmalonic aciduria and homocystinuria type cblE 0050732