rs1554687394

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_005458.8(GABBR2):​c.2743G>T​(p.Val915Phe) variant causes a missense change. The variant allele was found at a frequency of 0.00000151 in 1,324,086 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: not found (cov: 31)
Exomes 𝑓: 0.0000015 ( 0 hom. )

Consequence

GABBR2
NM_005458.8 missense

Scores

6
13

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 3.75

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

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (MetaRNN=0.1470288).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
GABBR2NM_005458.8 linkc.2743G>T p.Val915Phe missense_variant Exon 19 of 19 ENST00000259455.4 NP_005449.5 O75899H9NIL8
GABBR2XM_017015331.3 linkc.2449G>T p.Val817Phe missense_variant Exon 18 of 18 XP_016870820.1
GABBR2XM_005252316.6 linkc.1969G>T p.Val657Phe missense_variant Exon 17 of 17 XP_005252373.1
GABBR2XM_017015332.3 linkc.1969G>T p.Val657Phe missense_variant Exon 16 of 16 XP_016870821.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
GABBR2ENST00000259455.4 linkc.2743G>T p.Val915Phe missense_variant Exon 19 of 19 1 NM_005458.8 ENSP00000259455.2 O75899
GABBR2ENST00000637410.1 linkn.2521G>T non_coding_transcript_exon_variant Exon 19 of 19 5

Frequencies

GnomAD3 genomes
Cov.:
31
GnomAD4 exome
AF:
0.00000151
AC:
2
AN:
1324086
Hom.:
0
Cov.:
31
AF XY:
0.00000306
AC XY:
2
AN XY:
653058
show subpopulations
⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
26082
American (AMR)
AF:
0.00
AC:
0
AN:
17230
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
21628
East Asian (EAS)
AF:
0.00
AC:
0
AN:
31176
South Asian (SAS)
AF:
0.00
AC:
0
AN:
61946
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
50522
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5162
European-Non Finnish (NFE)
AF:
0.00000189
AC:
2
AN:
1055860
Other (OTH)
AF:
0.00
AC:
0
AN:
54480
⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.225
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
Cov.:
31

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:2
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Inborn genetic diseases Uncertain:1
Aug 03, 2017
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Epileptic encephalopathy Uncertain:1
Feb 22, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces valine, which is neutral and non-polar, with phenylalanine, which is neutral and non-polar, at codon 915 of the GABBR2 protein (p.Val915Phe). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with GABBR2-related conditions. ClinVar contains an entry for this variant (Variation ID: 521596). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. 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
Benign
0.13
BayesDel_addAF
Benign
-0.034
T
BayesDel_noAF
Benign
-0.29
CADD
Benign
23
DANN
Uncertain
0.99
DEOGEN2
Benign
0.13
T
Eigen
Benign
-0.022
Eigen_PC
Benign
0.19
FATHMM_MKL
Uncertain
0.90
D
LIST_S2
Uncertain
0.92
D
M_CAP
Benign
0.027
D
MetaRNN
Benign
0.15
T
MetaSVM
Benign
-0.48
T
MutationAssessor
Benign
0.0
N
PhyloP100
3.8
PrimateAI
Uncertain
0.52
T
PROVEAN
Benign
-0.95
N
REVEL
Benign
0.23
Sift
Uncertain
0.010
D
Sift4G
Uncertain
0.021
D
Polyphen
0.072
B
Vest4
0.18
MutPred
0.14
Loss of sheet (P = 0.0457);
MVP
0.36
MPC
1.3
ClinPred
0.83
D
GERP RS
5.5
Varity_R
0.23
gMVP
0.36
Mutation Taster
=86/14
polymorphism

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

Other links and lift over

dbSNP: rs1554687394; hg19: chr9-101052949; API