MAT1A

Chr 10

methionine adenosyltransferase 1A

Also known as: MAT, MATA1, SAMS, SAMS1

NCBI Gene: 4143 ENSG00000151224 UniProt: Q00266

This gene encodes methionine adenosyltransferase, which catalyzes the formation of S-adenosylmethionine from methionine and ATP, providing methyl groups for most biological methylations. Mutations cause methionine adenosyltransferase deficiency, presenting as persistent hypermethioninemia with both autosomal dominant and autosomal recessive inheritance patterns described. The gene shows low constraint against loss-of-function variants (pLI 0.0008, LOEUF 0.81), consistent with the observation that some individuals with deficiency may be asymptomatic.

GeneReviews ResearchSummary from RefSeq, OMIM, UniProt

This gene catalyzes a two-step reaction that involves the transfer of the adenosyl moiety of ATP to methionine to form S-adenosylmethionine and tripolyphosphate, which is subsequently cleaved to PPi and Pi. S-adenosylmethionine is the source of methyl groups for most biological methylations. The encoded protein is found as a homotetramer (MAT I) or a homodimer (MAT III) whereas a third form, MAT II (gamma), is encoded by the MAT2A gene. Mutations in this gene are associated with methionine adenosyltransferase deficiency. [provided by RefSeq, Jul 2008]

GeneReviews ResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

UniProtMethionine adenosyltransferase deficiency

Clinical highlights

Gene-disease validity (ClinGen)

methionine adenosyltransferase deficiency · ARDefinitivesufficient evidence for diagnostic panels

Interpreting a novel variant

Loss of function is the curated mechanism (Gene2Phenotype), though the gene is not strongly LoF-constrained in the population — weigh truncating variants against that tolerance.Curated gene-level mechanism — a prior for triage, not a per-variant call.

Active trials

Pubs (1 yr)

—

P/LP submissions

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P/LP missense

0.81

LOEUF

LOF

Mechanism· G2P

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GeneReview available — MAT1A