16-9938551-C-T

Variant names:

• chr16-9938551-C-T
• rs1555455852
• NM_001134407.3:c.415G>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_001134407.3(GRIN2A):​c.415G>A​(p.Asp139Asn) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000069 in 1,449,274 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. 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. D139Y) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: GRIN2A NM_001134407.3 missense, splice_region
• Scores: Splicing: ADA: 0.9997
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.81
• 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: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GRIN2A	NM_001134407.3	c.415G>A	p.Asp139Asn	missense_variant, splice_region_variant	Exon 3 of 13	ENST00000330684.4	NP_001127879.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GRIN2A	ENST00000330684.4	c.415G>A	p.Asp139Asn	missense_variant, splice_region_variant	Exon 3 of 13	1	NM_001134407.3	ENSP00000332549.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.90e-7 AC: 1 AN: 1449274 Hom.: 0 Cov.: 31 AF XY: 0.00000139 AC XY: 1 AN XY: 721402

⚠️ 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: 33450

American (AMR) AF: 0.00 AC: 0 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26120

East Asian (EAS) AF: 0.00 AC: 0 AN: 39646

South Asian (SAS) AF: 0.00 AC: 0 AN: 86234

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 41940

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111094

Other (OTH) AF: 0.00 AC: 0 AN: 60310

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.52
BayesDel_addAF	Benign	-0.047	T
BayesDel_noAF	Benign	-0.31
CADD	Pathogenic	32
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.46	T;.;.;T;.
Eigen	Pathogenic	0.86
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.53	.;T;D;D;T
M_CAP	Pathogenic	0.68	D
MetaRNN	Uncertain	0.71	D;D;D;D;D
MetaSVM	Uncertain	0.43	D
MutationAssessor	Uncertain	2.1	M;.;M;M;.
PhyloP100		7.8
PrimateAI	Uncertain	0.69	T
PROVEAN	Uncertain	-2.6	D;.;N;D;.
REVEL	Uncertain	0.51
Sift	Uncertain	0.0040	D;.;D;D;.
Sift4G	Uncertain	0.013	D;D;D;D;.
Polyphen		1.0	D;.;.;D;.
Vest4		0.75
MutPred		0.37		Loss of solvent accessibility (P = 0.0595);.;Loss of solvent accessibility (P = 0.0595);Loss of solvent accessibility (P = 0.0595);.;
MVP		0.93
MPC		1.6
ClinPred		0.99	D
GERP RS		5.5
Varity_R		0.56
gMVP		0.71

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.88
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: rs1555455852; hg19: chr16-10032408; COSMIC: COSV58022677;