7-126533530-C-T

Variant summary

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

The NM_000845.3(GRM8):c.1852G>A(p.Gly618Arg) 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. 13/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 30)
• Consequence: GRM8 NM_000845.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.90

Genes affected

GRM8 (HGNC:4600): (glutamate metabotropic receptor 8) 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. Alternatively spliced transcript variants encoding different isoforms have been described for this gene. [provided by RefSeq, Jul 2008]

LOC101928357 (HGNC:):

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, 0.91

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GRM8	NM_000845.3	c.1852G>A	p.Gly618Arg	missense_variant	9/11	ENST00000339582.7
LOC101928357	XR_927937.3	n.215-1222C>T		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GRM8	ENST00000339582.7	c.1852G>A	p.Gly618Arg	missense_variant	9/11	5	NM_000845.3	P1

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 30

Bravo AF: 0.00000378

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

Oct 04, 2022

The c.1852G>A (p.G618R) alteration is located in exon 9 (coding exon 8) of the GRM8 gene. This alteration results from a G to A substitution at nucleotide position 1852, causing the glycine (G) at amino acid position 618 to be replaced by an arginine (R). 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	1.0
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.43
Cadd	Pathogenic	31
Dann	Pathogenic	1.0
DEOGEN2	Uncertain	0.76	D;.;.
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	D;.;D
M_CAP	Pathogenic	0.48	D
MetaRNN	Pathogenic	0.91	D;D;D
MetaSVM	Pathogenic	0.92	D
MutationAssessor	Pathogenic	3.5	H;H;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.93	D
PROVEAN	Pathogenic	-7.5	D;D;.
REVEL	Pathogenic	0.86
Sift	Pathogenic	0.0	D;D;.
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.95
MutPred		0.52		Loss of methylation at R619 (P = 0.0644);Loss of methylation at R619 (P = 0.0644);.;
MVP		0.86
MPC		0.85
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.95
gMVP		0.96

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: rs1815186196; hg19: chr7-126173584;