Send to:

Choose Destination

Hepatic methionine adenosyltransferase deficiency

MedGen UID:
Concept ID:
Disease or Syndrome
Synonyms: Isolated Persistent Hypermethioninemia; MAT I/III DEFICIENCY
Modes of inheritance:
Autosomal recessive inheritance
MedGen UID:
Concept ID:
Intellectual Product
Sources: HPO, OMIM, Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele).
Autosomal dominant inheritance
MedGen UID:
Concept ID:
Intellectual Product
Sources: HPO, OMIM, Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele.
Autosomal recessive inheritance (HPO, OMIM, Orphanet)
Autosomal dominant inheritance (HPO, OMIM, Orphanet)
SNOMED CT: Methionine adenosyltransferase deficiency (57835009); Deficiency of methionine adenosyltransferase (124283007); Hepatic methionine adenosyltransferase deficiency (57835009); MAT deficiency (57835009)
Gene (location): MAT1A (10q22.3)
OMIM®: 250850
Orphanet: ORPHA168598


Methionine adenosyltransferase deficiency is an inborn error of metabolism resulting in isolated hypermethioninemia. Most patients have no clinical abnormalities, although some with the autosomal recessive form have have neurologic abnormalities (Mudd et al., 2003; Kim et al., 2016). [from OMIM]

Additional description

From GHR
Hypermethioninemia is an excess of a particular protein building block (amino acid), called methionine, in the blood. This condition can occur when methionine is not broken down (metabolized) properly in the body.People with hypermethioninemia often do not show any symptoms. Some individuals with hypermethioninemia exhibit intellectual disability and other neurological problems; delays in motor skills such as standing or walking; sluggishness; muscle weakness; liver problems; unusual facial features; and their breath, sweat, or urine may have a smell resembling boiled cabbage.Hypermethioninemia can occur with other metabolic disorders, such as homocystinuria, tyrosinemia and galactosemia, which also involve the faulty breakdown of particular molecules. It can also result from liver disease or excessive dietary intake of methionine from consuming large amounts of protein or a methionine-enriched infant formula.

Clinical features

From HPO
MedGen UID:
Concept ID:
Sign or Symptom
An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk.
MedGen UID:
Concept ID:
Autonomic nervous system overreaction to stimuli, most commonly after spinal cord injury at a T-5 level and above.
CNS demyelination
MedGen UID:
Concept ID:
Disease or Syndrome
A loss of myelin from nerve fibers in the central nervous system.
Peripheral demyelination
MedGen UID:
Concept ID:
Pathologic Function
A loss of myelin from the internode regions along myelinated nerve fibers of the peripheral nervous system.
Intellectual disability
MedGen UID:
Concept ID:
MedGen UID:
Concept ID:
Disease or Syndrome
An increased concentration of methionine in the blood.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVHepatic methionine adenosyltransferase deficiency
Follow this link to review classifications for Hepatic methionine adenosyltransferase deficiency in Orphanet.

Recent clinical studies


Gahl WA, Bernardini I, Finkelstein JD, Tangerman A, Martin JJ, Blom HJ, Mullen KD, Mudd SH
J Clin Invest 1988 Feb;81(2):390-7. doi: 10.1172/JCI113331. PMID: 3339126Free PMC Article


Chou JY
Pharmacol Ther 2000 Jan;85(1):1-9. doi: 10.1016/s0163-7258(99)00047-9. PMID: 10674710
Gahl WA, Finkelstein JD, Mullen KD, Bernardini I, Martin JJ, Backlund P, Ishak KG, Hoofnagle JH, Mudd SH
Am J Hum Genet 1987 Jan;40(1):39-49. PMID: 3812486Free PMC Article

Supplemental Content

Recent activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...
Support Center