Genetic Variant GABBR2:p.Gly133Gly (chr9-98577995-G-T) – ACMG Classification: Likely_benign (-3 pts)

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2BP4_StrongBP7

The NM_005458.8(GABBR2):c.399C>A(p.Gly133Gly) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,436 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. G133G) has been classified as Benign.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

GABBR2
NM_005458.8 synonymous

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 0.0740

Publications

0 publications found

Variant links:

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]

GABBR2 Gene-Disease associations (from GenCC):

developmental and epileptic encephalopathy, 59
Inheritance: AD Classification: STRONG, MODERATE Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
neurodevelopmental disorder with poor language and loss of hand skills
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
atypical Rett syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

GABBR2 links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.53).

BP7

Synonymous conserved (PhyloP=0.074 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GABBR2	NM_005458.8 link	c.399C>A	p.Gly133Gly	synonymous_variant	Exon 2 of 19	ENST00000259455.4	NP_005449.5	O75899H9NIL8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
GABBR2	ENST00000259455.4 link	c.399C>A	p.Gly133Gly	synonymous_variant	Exon 2 of 19	1	NM_005458.8	ENSP00000259455.2	O75899
GABBR2	ENST00000637717.1 link	c.15C>A	p.Gly5Gly	synonymous_variant	Exon 2 of 3	5		ENSP00000490789.1	A0A1B0GW60
GABBR2	ENST00000634227.1 link	n.173C>A		non_coding_transcript_exon_variant	Exon 2 of 6	5
GABBR2	ENST00000637410.1 link	n.177C>A		non_coding_transcript_exon_variant	Exon 2 of 19	5

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461436

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727056

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33460

American (AMR)

AF:

0.00

AC:

AN:

44716

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39692

South Asian (SAS)

AF:

0.00

AC:

AN:

86240

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

9.00e-7

AC:

AN:

1111630

Other (OTH)

AF:

0.00

AC:

AN:

60382

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.53

CADD

Benign

1.8

(source)

DANN

Benign

0.80

PhyloP100

0.074

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over