NM_021956.5:c.222T>C

Variant names:

• chr6-101622055-T-C
• rs112817493
• NM_021956.5:c.222T>C

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 0P and 6B. BP4_Strong BP7 BS1_Supporting

The NM_021956.5(GRIK2):​c.222T>C​(p.Thr74Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000687 in 1,601,772 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000069 (0 hom.)
• Consequence: GRIK2 NM_021956.5 synonymous
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.00400
• Publications: 0 publications found

Genes affected

GRIK2 (HGNC:4580): (glutamate ionotropic receptor kainate 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 the kainate family of glutamate receptors, which are composed of four subunits and function as ligand-activated ion channels. The subunit encoded by this gene is subject to RNA editing at multiple sites within the first and second transmembrane domains, which is thought to alter the structure and function of the receptor complex. Alternatively spliced transcript variants encoding different isoforms have also been described for this gene. Mutations in this gene have been associated with autosomal recessive cognitive disability. [provided by RefSeq, Jul 2008]

GRIK2 Gene-Disease associations (from GenCC):

• complex neurodevelopmental disorder

  Inheritance: AR, AD Classification: DEFINITIVE, MODERATE Submitted by: ClinGen
• intellectual disability, autosomal recessive 6

  Inheritance: AR Classification: DEFINITIVE, STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
• neurodevelopmental disorder with impaired language and ataxia and with or without seizures

  Inheritance: AD Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• autosomal recessive non-syndromic intellectual disability

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -6 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.52).
• BP7: Synonymous conserved (PhyloP=-0.004 with no splicing effect.
• BS1: Variant frequency is greater than expected in population afr. GnomAdExome4 allele frequency = 0.0000069 (10/1449640) while in subpopulation AFR AF = 0.000301 (10/33244). AF 95% confidence interval is 0.000162. There are 0 homozygotes in GnomAdExome4. There are 5 alleles in the male GnomAdExome4 subpopulation. Median coverage is 27. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GRIK2	NM_021956.5	c.222T>C	p.Thr74Thr	synonymous_variant	Exon 3 of 17	ENST00000369134.9	NP_068775.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GRIK2	ENST00000369134.9	c.222T>C	p.Thr74Thr	synonymous_variant	Exon 3 of 17	5	NM_021956.5	ENSP00000358130.6

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152132 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000690 AC: 10 AN: 1449640 Hom.: 0 Cov.: 27 AF XY: 0.00000692 AC XY: 5 AN XY: 722142

African (AFR) AF: 0.000301 AC: 10 AN: 33244

American (AMR) AF: 0.00 AC: 0 AN: 44712

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26056

East Asian (EAS) AF: 0.00 AC: 0 AN: 39542

South Asian (SAS) AF: 0.00 AC: 0 AN: 86020

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53344

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5744

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1101036

Other (OTH) AF: 0.00 AC: 0 AN: 59942

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152132 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74298

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

African (AFR) AF: 0.0000241 AC: 1 AN: 41446

American (AMR) AF: 0.00 AC: 0 AN: 15252

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5184

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10614

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68016

Other (OTH) AF: 0.00 AC: 0 AN: 2094

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

Asia WGS AF: 0.00115 AC: 4 AN: 3476

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Sep 23, 2015

Genetic Services Laboratory, University of Chicago

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.52
CADD	Benign	5.0
DANN	Benign	0.64
PhyloP100		-0.0040
Mutation Taster		=84/16	polymorphism

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

Other links and lift over

dbSNP: rs112817493; hg19: chr6-102069930;