21-29576980-G-A

Position:

• chr21-29576980-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_001330994.2(GRIK1):​c.2114C>T​(p.Thr705Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000662 in 151,044 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: GRIK1 NM_001330994.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.93

Genes affected

GRIK1 (HGNC:4579): (glutamate ionotropic receptor kainate type subunit 1) 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 (CAG->CGG; Q->R) within the second transmembrane domain, which is thought to alter the properties of ion flow. Alternative splicing, resulting in transcript variants encoding different isoforms, has been noted for this gene. [provided by RefSeq, Jul 2008]

LOC105372768 (HGNC:):

BACH1 (HGNC:935): (BTB domain and CNC homolog 1) This gene encodes a transcription factor that belongs to the cap'n'collar type of basic region leucine zipper factor family (CNC-bZip). The encoded protein contains broad complex, tramtrack, bric-a-brac/poxvirus and zinc finger (BTB/POZ) domains, which is atypical of CNC-bZip family members. These BTB/POZ domains facilitate protein-protein interactions and formation of homo- and/or hetero-oligomers. When this encoded protein forms a heterodimer with MafK, it functions as a repressor of Maf recognition element (MARE) and transcription is repressed. Multiple alternatively spliced transcript variants have been identified for this gene. [provided by RefSeq, May 2009]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.956

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GRIK1	NM_001330994.2	c.2114C>T	p.Thr705Ile	missense_variant	14/18	ENST00000327783.9	NP_001317923.1
LOC105372768	XR_937647.3	n.173-50G>A		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GRIK1	ENST00000327783.9	c.2114C>T	p.Thr705Ile	missense_variant	14/18	5	NM_001330994.2	ENSP00000327687	A1

Frequencies

GnomAD3 genomes AF: 0.00000662 AC: 1 AN: 151044 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000194

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

GnomAD3 exomes AF: 0.00000797 AC: 2 AN: 250896 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135638

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000109

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 29

GnomAD4 genome AF: 0.00000662 AC: 1 AN: 151044 Hom.: 0 Cov.: 32 AF XY: 0.0000136 AC XY: 1 AN XY: 73628

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000194

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 23, 2021

The c.2114C>T (p.T705I) alteration is located in exon 14 (coding exon 14) of the GRIK1 gene. This alteration results from a C to T substitution at nucleotide position 2114, causing the threonine (T) at amino acid position 705 to be replaced by an isoleucine (I). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Uncertain	0.080	D
BayesDel_noAF	Uncertain	0.10
CADD	Pathogenic	31
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.68	.;.;.;.;.;D;D
Eigen	Pathogenic	0.99
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D;D;D;D;D;D
M_CAP	Benign	0.017	T
MetaRNN	Pathogenic	0.96	D;D;D;D;D;D;D
MetaSVM	Benign	-0.84	T
MutationAssessor	Uncertain	2.7	.;.;.;.;.;M;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-5.5	D;D;D;D;D;D;D
REVEL	Pathogenic	0.73
Sift	Pathogenic	0.0	D;D;D;D;D;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D;D;D;D
Polyphen		1.0	.;D;D;D;.;D;.
Vest4		0.85
MutPred		0.90		.;Loss of disorder (P = 0.0577);.;Loss of disorder (P = 0.0577);.;.;Loss of disorder (P = 0.0577);
MVP		0.77
MPC		0.84
ClinPred		0.99	D
GERP RS		5.3
Varity_R		0.96
gMVP		0.91

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs763922363; hg19: chr21-30949300;