chr16-9768993-G-C

Variant names:

• chr16-9768993-G-C
• rs751455326
• NM_001134407.3:c.2453C>G

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PM2 PM5

The NM_001134407.3(GRIN2A):​c.2453C>G​(p.Ala818Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,820 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A818T) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: GRIN2A NM_001134407.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.88
• Publications: 0 publications found

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]

GRIN2A Gene-Disease associations (from GenCC):

• complex neurodevelopmental disorder

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• Landau-Kleffner syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• continuous spikes and waves during sleep

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• early-onset epileptic encephalopathy and intellectual disability due to GRIN2A mutation

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• rolandic epilepsy-speech dyspraxia syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• self-limited epilepsy with centrotemporal spikes

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• neurodevelopmental disorder

  Inheritance: AR Classification: LIMITED Submitted by: G2P

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_001134407.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr16-9768994-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 522855.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001134407.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GRIN2A	NM_001134407.3	MANE Select	c.2453C>G	p.Ala818Gly	missense	Exon 12 of 13	NP_001127879.1
	GRIN2A	NM_000833.5		c.2453C>G	p.Ala818Gly	missense	Exon 13 of 14	NP_000824.1
	GRIN2A	NM_001134408.2		c.2453C>G	p.Ala818Gly	missense	Exon 12 of 14	NP_001127880.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GRIN2A	ENST00000330684.4	TSL:1 MANE Select	c.2453C>G	p.Ala818Gly	missense	Exon 12 of 13	ENSP00000332549.3
	GRIN2A	ENST00000396573.6	TSL:1	c.2453C>G	p.Ala818Gly	missense	Exon 13 of 14	ENSP00000379818.2
	GRIN2A	ENST00000562109.5	TSL:1	c.2453C>G	p.Ala818Gly	missense	Exon 12 of 14	ENSP00000454998.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461820 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727220

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111946

Other (OTH) AF: 0.00 AC: 0 AN: 60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.92
BayesDel_addAF	Uncertain	0.090	D
BayesDel_noAF	Benign	-0.11
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.82	D
Eigen	Uncertain	0.66
Eigen_PC	Uncertain	0.65
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Pathogenic	0.60	D
MetaRNN	Uncertain	0.69	D
MetaSVM	Benign	-0.77	T
MutationAssessor	Benign	1.5	L
PhyloP100		9.9
PrimateAI	Pathogenic	0.81	D
PROVEAN	Uncertain	-3.6	D
REVEL	Uncertain	0.32
Sift	Uncertain	0.0090	D
Sift4G	Uncertain	0.0060	D
Polyphen		1.0	D
Vest4		0.70
MutPred		0.60		Loss of helix (P = 0.079)
MVP		0.71
MPC		0.90
ClinPred		0.99	D
GERP RS		4.5
Varity_R		0.81
gMVP		0.88

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs751455326; hg19: chr16-9862850;