6-146029644-G-A

Position:

• chr6-146029644-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP2 PP3_Strong

The NM_001278064.2(GRM1):​c.127G>A​(p.Gly43Arg) 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. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: GRM1 NM_001278064.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.00

Genes affected

GRM1 (HGNC:4593): (glutamate metabotropic receptor 1) This gene encodes a metabotropic glutamate receptor that functions by activating phospholipase C. 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 canonical alpha isoform of the encoded protein is a disulfide-linked homodimer whose activity is mediated by a G-protein-coupled phosphatidylinositol-calcium second messenger system. This gene may be associated with many disease states, including schizophrenia, bipolar disorder, depression, and breast cancer. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, May 2013]

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), GRM1. . Gene score misZ 2.5817 (greater than the threshold 3.09). Trascript score misZ 3.6372 (greater than threshold 3.09). GenCC has associacion of gene with spinocerebellar ataxia 44, autosomal recessive spinocerebellar ataxia 13.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.969

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GRM1	NM_001278064.2	c.127G>A	p.Gly43Arg	missense_variant	1/8	ENST00000282753.6	NP_001264993.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GRM1	ENST00000282753.6	c.127G>A	p.Gly43Arg	missense_variant	1/8	1	NM_001278064.2	ENSP00000282753	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 06, 2018

This sequence change replaces glycine with arginine at codon 43 of the GRM1 protein (p.Gly43Arg). The glycine residue is moderately conserved and there is a moderate physicochemical difference between glycine and arginine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with GRM1-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.41
CADD	Pathogenic	32
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.65	.;D;.;D;.
Eigen	Pathogenic	0.93
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Benign	0.57	D
LIST_S2	Pathogenic	0.97	.;D;D;.;D
M_CAP	Uncertain	0.28	D
MetaRNN	Pathogenic	0.97	D;D;D;D;D
MetaSVM	Uncertain	0.77	D
MutationAssessor	Pathogenic	3.0	M;M;M;M;M
MutationTaster	Benign	1.0	D;D;D;D;D;D
PrimateAI	Pathogenic	0.88	D
PROVEAN	Pathogenic	-7.1	D;D;D;D;D
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	D;D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D;D
Polyphen		1.0	D;D;.;D;D
Vest4		0.94
MutPred		0.84		Gain of MoRF binding (P = 0.015);Gain of MoRF binding (P = 0.015);Gain of MoRF binding (P = 0.015);Gain of MoRF binding (P = 0.015);Gain of MoRF binding (P = 0.015);
MVP		0.93
MPC		1.9
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.96
gMVP		0.95

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: rs1790639703; hg19: chr6-146350780; COSMIC: COSV51183854;