4-157221720-A-G

Variant names:

• chr4-157221720-A-G
• ENST00000393815.6:c.1A>G

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PVS1_Supporting PM2

The NM_001083620.3(GRIA2):​c.1A>G​(p.Met1?) variant causes a start lost change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: GRIA2 NM_001083620.3 start_lost
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.22

Genes affected

GRIA2 (HGNC:4572): (glutamate ionotropic receptor AMPA type subunit 2) Glutamate receptors are the predominant excitatory neurotransmitter receptors in the mammalian brain and are activated in a variety of normal neurophysiologic processes. This gene product belongs to a family of glutamate receptors that are sensitive to alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA), and function as ligand-activated cation channels. These channels are assembled from 4 related subunits, GRIA1-4. The subunit encoded by this gene (GRIA2) is subject to RNA editing (CAG->CGG; Q->R) within the second transmembrane domain, which is thought to render the channel impermeable to Ca(2+). Human and animal studies suggest that pre-mRNA editing is essential for brain function, and defective GRIA2 RNA editing at the Q/R site may be relevant to amyotrophic lateral sclerosis (ALS) etiology. Alternative splicing, resulting in transcript variants encoding different isoforms, (including the flip and flop isoforms that vary in their signal transduction properties), has been noted for this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PVS1: Start lost variant, no pathogenic variants between lost start and next in-frame start position. Next in-frame start position is after 81 codons. Genomic position: 157303704. Lost 0.096 part of the original CDS.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GRIA2	NM_001083619.3	c.142A>G	p.Met48Val	missense_variant	Exon 2 of 16	ENST00000264426.14	NP_001077088.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GRIA2	ENST00000264426.14	c.142A>G	p.Met48Val	missense_variant	Exon 2 of 16	1	NM_001083619.3	ENSP00000264426.9

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Feb 17, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.31
BayesDel_addAF	Uncertain	0.074	D
BayesDel_noAF	Benign	-0.13
CADD	Benign	22
DANN	Uncertain	0.99
DEOGEN2	Benign	0.13	.;.;.;.;.;.;T;.;T
Eigen	Benign	-0.12
Eigen_PC	Benign	0.096
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Pathogenic	0.98	D;.;D;D;D;D;D;D;D
M_CAP	Benign	0.012	T
MetaRNN	Benign	0.37	T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.55	.;.;.;.;N;N;N;.;.
PrimateAI	Pathogenic	0.82	D
PROVEAN	Benign	-1.3	N;N;N;N;.;N;N;N;N
REVEL	Benign	0.17
Sift	Uncertain	0.010	D;D;D;T;.;T;T;D;D
Sift4G	Benign	0.16	T;D;D;T;.;T;T;D;D
Polyphen		0.010, 0.016	.;.;.;.;.;B;B;.;.
Vest4		0.74, 0.46, 0.57
MutPred		0.53		Loss of methylation at R45 (P = 0.1312);.;.;Loss of methylation at R45 (P = 0.1312);Loss of methylation at R45 (P = 0.1312);Loss of methylation at R45 (P = 0.1312);Loss of methylation at R45 (P = 0.1312);.;.;
MVP		0.62
MPC		0.63
ClinPred		0.82	D
GERP RS		5.5
Varity_R		0.62
gMVP		0.88

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr4-158142872;