Homocystinuria-megaloblastic anemia, cblg type

Preferred Label : Homocystinuria-megaloblastic anemia, cblg type;

Symbol : HMAG;

CISMeF acronym : HMAG;

Type : Phenotype, molecular basis known;

Alternative titles and symbols : Homocystinuria-megaloblastic anemia due to defect in cobalamin metabolism, cblg complementation type; Methylcobalamin deficiency, cblg type; Methionine synthase deficiency;

Description : Homocystinuria and megaloblastic anemia is an autosomal recessive inborn error of metabolism resulting from defects in the cobalamin (vitamin B12)-dependent pathway that converts homocysteine to methionine, which is catalyzed by methionine synthase. Clinical features are somewhat variable, but include delayed psychomotor development, megaloblastic anemia, homocystinuria, and hypomethioninemia, all of which respond to cobalamin supplementation. Methylmalonic aciduria is not present. Two complementation groups have been described based on fibroblast studies: CblE (236270) and CblG (Watkins and Rosenblatt, 1988). Most patients present in early infancy, but some patients with CblG have shown later onset (Outteryck et al., 2012). Cells from patients with CblE fail to incorporate methyltetrahydrofolate into methionine in whole cells, but cell extracts show normal methionine synthase activity in the presence of a reducing agent. Cells from patients with CblG have defects in the methionine synthase enzyme under both conditions (summary by Leclerc et al., 1996). CblE is caused by mutation in the MTRR gene (602568). Watkins and Rosenblatt (1989) commented on the clinical and biochemical heterogeneity in patients with cblE and cblG.;

Inheritance : Autosomal recessive;

Molecular basis : Caused by mutation in the methionine synthase gene (MTR, 156570.0001);

Laboratory abnormalities : Hypomethioninemia; Homocystinuria; Hyperhomocystinemia;

Prefixed ID : #250940;

Details

Origin ID

250940;

UMLS CUI

C1855128;

Automatic exact mappings (from CISMeF team)
- Arakawa Syndrome II [NCIt concept]
- Decreased methionine synthase activity [HPO term]
- Homocystinuria without methylmalonic aciduria [ORDO Disease]
Currated CISMeF NLP mapping
- Methylcobalamin deficiency type cbl G [ICD-11 More detail]
- Methylcobalamin deficiency type cbl G (disorder) [SNOMED CT concept]
- Methylcobalamin deficiency type cblG [ORDO Disease]
- Methylcobalamin, cbl g, deficiency [HPO term]
- methylcobalamin deficiency, CblG type [MeSH concept]
- methylcobalamin deficiency, CblG type [MeSH Supplementary Concept]
Genes related to phenotype
- 5-methyltetrahydrofolate-homocysteine s-methyltransferase [OMIM gene]
HPO term(s)
- Autosomal recessive inheritance [HPO term]
- Blindness [HPO term]
- Cerebral atrophy [HPO term]
- Decreased methionine synthase activity [HPO term]
- Decreased methylcobalamin [HPO term]
- Failure to thrive [HPO term]
- Feeding difficulties [HPO term]
- Feeding difficulties in infancy [HPO term]
- Gait disturbance [HPO term]
- Generalized hypotonia [HPO term]
- Global developmental delay [HPO term]
- Homocystinuria [HPO term]
- Hyperhomocystinemia [HPO term]
- Hypomethioninemia [HPO term]
- Hypotonia [HPO term]
- Infantile onset [HPO term]
- Intellectual disability [HPO term]
- Megaloblastic anemia [HPO term]
- Methylcobalamin, cbl g, deficiency [HPO term]
- Nystagmus [HPO term]
- Poor coordination [HPO term]
- Seizure [HPO term]
Not associated HPO term(s)
- Methylmalonic acidemia [HPO term]
- Methylmalonic aciduria [HPO term]
ORDO concept(s)
- Homocystinuria without methylmalonic aciduria [ORDO Disease]
- Methylcobalamin deficiency type cblG [ORDO Disease]
See also inter- (CISMeF)
- Homocystinuria without methylmalonic aciduria [ICD-11 More detail]
Semantic type(s)
- Disease or Syndrome [UMLS semantic type]
UMLS correspondences (same concept)
- Methylcobalamin deficiency type cblG [ORDO Disease]
- methylcobalamin deficiency, CblG type [MeSH Supplementary Concept]
- methylcobalamin deficiency, CblG type [MeSH concept]

Keyword's position in hierarchy(ies) :

You can consult :

recommendations
documents concerning education
documents for patients