10-80275071-GCG-ACA

Variant names:

• chr10-80275071-GCG-ACA
• NM_000429.3:c.895_897delCGCinsTGT
• MAT1A p.Arg299Cys

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PS1_Very_Strong PM1 PM5 PP2 PP3

The NM_000429.3(MAT1A):​c.895_897delCGCinsTGT​(p.Arg299Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely pathogenic in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R299H) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: MAT1A NM_000429.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.60
• Publications: 0 publications found

Genes affected

MAT1A (HGNC:6903): (methionine adenosyltransferase 1A) 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]

MAT1A Gene-Disease associations (from GenCC):

• methionine adenosyltransferase deficiency

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, ClinGen, Orphanet, G2P, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Pathogenic. The variant received 14 ACMG points.

• PS1: Transcript NM_000429.3 (MAT1A) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_000429.3
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr10-80275072-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 858071.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 20 curated pathogenic missense variants (we use a threshold of 10). The gene has 0 curated benign missense variants. Gene score misZ: 1.654 (below the threshold of 3.09). Trascript score misZ: 2.3811 (below the threshold of 3.09). GenCC associations: The gene is linked to methionine adenosyltransferase deficiency.
• PP3: No computational evidence supports a deleterious effect, but strongly conserved according to phyloP

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000429.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MAT1A	NM_000429.3	MANE Select	c.895_897delCGCinsTGT	p.Arg299Cys	missense	N/A	NP_000420.1	Q00266

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MAT1A	ENST00000372213.8	TSL:1 MANE Select	c.895_897delCGCinsTGT	p.Arg299Cys	missense	N/A	ENSP00000361287.3	Q00266
	MAT1A	ENST00000871627.1		c.895_897delCGCinsTGT	p.Arg299Cys	missense	N/A	ENSP00000541686.1
	MAT1A	ENST00000871624.1		c.1060_1062delCGCinsTGT	p.Arg354Cys	missense	N/A	ENSP00000541683.1

Frequencies

GnomAD3 genomes Cov.: 33

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		9.6

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr10-82034827;