chr16-9849914-C-A

Variant names:

• chr16-9849914-C-A
• rs1555496181
• NM_001134407.3:c.1170G>T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_001134407.3(GRIN2A):​c.1170G>T​(p.Trp390Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: GRIN2A NM_001134407.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 7.81

Genes affected

GRIN2A (HGNC:4585): (glutamate ionotropic receptor NMDA type subunit 2A) This gene encodes a member of the glutamate-gated ion channel protein family. The encoded protein is an N-methyl-D-aspartate (NMDA) receptor subunit. NMDA receptors are both ligand-gated and voltage-dependent, and are involved in long-term potentiation, an activity-dependent increase in the efficiency of synaptic transmission thought to underlie certain kinds of memory and learning. These receptors are permeable to calcium ions, and activation results in a calcium influx into post-synaptic cells, which results in the activation of several signaling cascades. Disruption of this gene is associated with focal epilepsy and speech disorder with or without cognitive disability. Alternative splicing results in multiple transcript variants. [provided by RefSeq, May 2014]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the GRIN2A gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 92 curated pathogenic missense variants (we use a threshold of 10). The gene has 175 curated benign missense variants. Gene score misZ: 2.8278 (below the threshold of 3.09). Trascript score misZ: 3.7088 (above the threshold of 3.09). GenCC associations: The gene is linked to early-onset epileptic encephalopathy and intellectual disability due to GRIN2A mutation, Landau-Kleffner syndrome, continuous spikes and waves during sleep, complex neurodevelopmental disorder, rolandic epilepsy-speech dyspraxia syndrome, childhood epilepsy with centrotemporal spikes.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.922

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GRIN2A	NM_001134407.3	c.1170G>T	p.Trp390Cys	missense_variant	Exon 5 of 13	ENST00000330684.4	NP_001127879.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GRIN2A	ENST00000330684.4	c.1170G>T	p.Trp390Cys	missense_variant	Exon 5 of 13	1	NM_001134407.3	ENSP00000332549.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Landau-Kleffner syndrome Uncertain:1

Nov 20, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. This sequence change replaces tryptophan, which is neutral and slightly polar, with cysteine, which is neutral and slightly polar, at codon 390 of the GRIN2A protein (p.Trp390Cys). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with GRIN2A-related conditions. ClinVar contains an entry for this variant (Variation ID: 532710). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt GRIN2A protein function. -

not provided Uncertain:1

Mar 15, 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 has a deleterious effect on protein structure/function; In addition, in silico analysis suggests this variant may impact gene splicing. In the absence of RNA/functional studies, the actual effect of this sequence change is unknown.; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.50
CADD	Pathogenic	34
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.92	D;.;.;D
Eigen	Pathogenic	0.86
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	.;D;D;D
M_CAP	Pathogenic	0.92	D
MetaRNN	Pathogenic	0.92	D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.7	M;.;M;M
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-12	D;.;D;D
REVEL	Pathogenic	0.91
Sift	Uncertain	0.0010	D;.;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D
Polyphen		1.0	D;.;.;D
Vest4		0.96
MutPred		0.54		Loss of MoRF binding (P = 0.0478);.;Loss of MoRF binding (P = 0.0478);Loss of MoRF binding (P = 0.0478);
MVP		0.96
MPC		2.0
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.83
gMVP		0.99

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.47		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.47		Position offset: -6

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555496181; hg19: chr16-9943771;