9-98290610-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_005458.8(GABBR2):c.2800T>C(p.Phe934Leu) 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 benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: GABBR2 NM_005458.8 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.56

Genes affected

GABBR2 (HGNC:4507): (gamma-aminobutyric acid type B receptor subunit 2) The multi-pass membrane protein encoded by this gene belongs to the G-protein coupled receptor 3 family and GABA-B receptor subfamily. The GABA-B receptors inhibit neuronal activity through G protein-coupled second-messenger systems, which regulate the release of neurotransmitters, and the activity of ion channels and adenylyl cyclase. This receptor subunit forms an active heterodimeric complex with GABA-B receptor subunit 1, neither of which is effective on its own. Allelic variants of this gene have been associated with nicotine dependence.[provided by RefSeq, Jan 2010]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, GABBR2
• BP4: Computational evidence support a benign effect (MetaRNN=0.19218332).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GABBR2	NM_005458.8	c.2800T>C	p.Phe934Leu	missense_variant	19/19	ENST00000259455.4
GABBR2	XM_017015331.3	c.2506T>C	p.Phe836Leu	missense_variant	18/18
GABBR2	XM_005252316.6	c.2026T>C	p.Phe676Leu	missense_variant	17/17
GABBR2	XM_017015332.3	c.2026T>C	p.Phe676Leu	missense_variant	16/16

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GABBR2	ENST00000259455.4	c.2800T>C	p.Phe934Leu	missense_variant	19/19	1	NM_005458.8	P1
GABBR2	ENST00000637410.1			downstream_gene_variant		5

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1266580 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 617158

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Epileptic encephalopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 11, 2022

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. 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: "Benign"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals affected with GABBR2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces phenylalanine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 934 of the GABBR2 protein (p.Phe934Leu). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.92
BayesDel_addAF	Uncertain	0.053	T
BayesDel_noAF	Benign	-0.16
Cadd	Benign	23
Dann	Uncertain	1.0
DEOGEN2	Benign	0.083	T
Eigen	Benign	0.046
Eigen_PC	Uncertain	0.25
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.89	D
M_CAP	Benign	0.030	D
MetaRNN	Benign	0.19	T
MetaSVM	Benign	-0.60	T
MutationAssessor	Benign	0.34	N
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.83	D
PROVEAN	Benign	-0.51	N
REVEL	Benign	0.29
Sift	Uncertain	0.0080	D
Sift4G	Uncertain	0.026	D
Polyphen		0.13	B
Vest4		0.29
MutPred		0.22		Gain of glycosylation at S933 (P = 0.053);
MVP		0.62
MPC		1.1
ClinPred		0.82	D
GERP RS		5.5
Varity_R		0.24
gMVP		0.39

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: rs1012965260; hg19: chr9-101052892;