homocystinuria-megaloblastic anemia—cblE complementation type
METABOLISM, MOLECULAR MEDICINE
An autosomal recessive condition (OMIM:236270) characterised defects in the cobalamin (vitamin B12)-dependent pathway, in which methionine synthase normally converts homocysteine to methionine
Clinical features Variable, including developmental delay, hypotonia, megaloblastic anaemia, homocystinuria, and hypomethioninemia–and with that, an increased risk of cardiovascular disease and neural tube defects. The defects respond to cobalamin supplementation.
Molecular pathology Defects in MTRR, which encodes an enzyme involved in the reductive regeneration of cobalamin cofactor, cause homocystinuria-megaloblastic anemia—cblE complementation type.
Synonyms Methylcobalamin deficiency type E, vitamin B12-responsive homocystinuria