7-126533086-A-G

Position:

• chr7-126533086-A-G

Variant summary

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

The NM_000845.3(GRM8):​c.2296T>C​(p.Tyr766His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,700 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 29)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: GRM8 NM_000845.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.32

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]

GRM8 (HGNC:):

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, 0.964

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GRM8	NM_000845.3	c.2296T>C	p.Tyr766His	missense_variant	9/11	ENST00000339582.7	NP_000836.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GRM8	ENST00000339582.7	c.2296T>C	p.Tyr766His	missense_variant	9/11	5	NM_000845.3	ENSP00000344173.2

Frequencies

GnomAD3 genomes Cov.: 29

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461700 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727172

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 29

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 09, 2024

The c.2296T>C (p.Y766H) alteration is located in exon 9 (coding exon 8) of the GRM8 gene. This alteration results from a T to C substitution at nucleotide position 2296, causing the tyrosine (Y) at amino acid position 766 to be replaced by a histidine (H). 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	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.28
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.87	D;.;.
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.92
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Pathogenic	0.98	D;.;D
M_CAP	Pathogenic	0.35	D
MetaRNN	Pathogenic	0.96	D;D;D
MetaSVM	Pathogenic	0.93	D
MutationAssessor	Pathogenic	3.3	M;M;.
PrimateAI	Pathogenic	0.93	D
PROVEAN	Pathogenic	-4.7	D;D;.
REVEL	Pathogenic	0.91
Sift	Pathogenic	0.0	D;D;.
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.94
MutPred		0.88		Gain of methylation at K769 (P = 0.0478);Gain of methylation at K769 (P = 0.0478);.;
MVP		0.79
MPC		0.89
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.92
gMVP		0.88

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr7-126173140;