NM_000840.3:c.661G>T

Variant names:

• chr7-86786453-G-T
• rs1797247825
• NM_000840.3:c.661G>T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_000840.3(GRM3):​c.661G>T​(p.Asp221Tyr) 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: GRM3 NM_000840.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.89

Genes affected

GRM3 (HGNC:4595): (glutamate metabotropic receptor 3) L-glutamate is the major excitatory neurotransmitter in the central nervous system and activates both ionotropic and metabotropic glutamate receptors. Glutamatergic neurotransmission is involved in most aspects of normal brain function and can be perturbed in many neuropathologic conditions. The metabotropic glutamate receptors are a family of G protein-coupled receptors, that have been divided into 3 groups on the basis of sequence homology, putative signal transduction mechanisms, and pharmacologic properties. Group I includes GRM1 and GRM5 and these receptors have been shown to activate phospholipase C. Group II includes GRM2 and GRM3 while Group III includes GRM4, GRM6, GRM7 and GRM8. Group II and III receptors are linked to the inhibition of the cyclic AMP cascade but differ in their agonist selectivities. [provided by RefSeq, Jul 2008]

GRM3-AS1 (HGNC:40264): (GRM3 antisense RNA 1)

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.907

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GRM3	NM_000840.3	c.661G>T	p.Asp221Tyr	missense_variant	Exon 3 of 6	ENST00000361669.7	NP_000831.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GRM3	ENST00000361669.7	c.661G>T	p.Asp221Tyr	missense_variant	Exon 3 of 6	1	NM_000840.3	ENSP00000355316.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000370 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Jan 10, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.661G>T (p.D221Y) alteration is located in exon 3 (coding exon 2) of the GRM3 gene. This alteration results from a G to T substitution at nucleotide position 661, causing the aspartic acid (D) at amino acid position 221 to be replaced by a tyrosine (Y). 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	0.94
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.43
CADD	Pathogenic	30
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.83	D;.;.
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.95
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.97	D;D;D
M_CAP	Uncertain	0.18	D
MetaRNN	Pathogenic	0.91	D;D;D
MetaSVM	Pathogenic	0.81	D
MutationAssessor	Pathogenic	3.9	H;.;H
PrimateAI	Pathogenic	0.88	D
PROVEAN	Pathogenic	-4.4	D;D;D
REVEL	Pathogenic	0.93
Sift	Uncertain	0.0020	D;D;D
Sift4G	Uncertain	0.0030	D;D;D
Polyphen		1.0	D;.;.
Vest4		0.92
MutPred		0.63		Loss of disorder (P = 0.0371);.;Loss of disorder (P = 0.0371);
MVP		0.98
MPC		2.6
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.91
gMVP		0.86

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

Publications

LitVar

Other links and lift over

dbSNP: rs1797247825; hg19: chr7-86415769; COSMIC: COSV64467774;