rs1057520498

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PM1PM2PP3_ModeratePP5_Very_Strong

The NM_198904.4(GABRG2):c.269C>T(p.Thr90Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000275 in 1,452,292 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. T90T) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000028 ( 0 hom. )

Consequence

GABRG2
NM_198904.4 missense

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:6U:1

Conservation

PhyloP100: 7.48

Publications

9 publications found

Variant links:

Genes affected

GABRG2 (HGNC:4087): (gamma-aminobutyric acid type A receptor subunit gamma2) This gene encodes a gamma-aminobutyric acid (GABA) receptor. GABA is the major inhibitory neurotransmitter in the mammlian brain, where it acts at GABA-A receptors, which are ligand-gated chloride channels. GABA-A receptors are pentameric, consisting of proteins from several subunit classes: alpha, beta, gamma, delta and rho. Mutations in this gene have been associated with epilepsy and febrile seizures. Multiple transcript variants encoding different isoforms have been identified for this gene. [provided by RefSeq, Jul 2008]

GABRG2 Gene-Disease associations (from GenCC):

epilepsy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
developmental and epileptic encephalopathy, 74
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
febrile seizures, familial, 8
Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae)
Dravet syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
generalized epilepsy with febrile seizures plus
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
self-limited epilepsy with centrotemporal spikes
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
undetermined early-onset epileptic encephalopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

GABRG2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 14 ACMG points.

PM1

In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_198904.4

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.886

PP5

Variant 5-162095504-C-T is Pathogenic according to our data. Variant chr5-162095504-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 379114.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GABRG2	NM_198904.4 link	c.269C>T	p.Thr90Met	missense_variant	Exon 3 of 10	ENST00000639213.2	NP_944494.1	P18507-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GABRG2	ENST00000639213.2 link	c.269C>T	p.Thr90Met	missense_variant	Exon 3 of 10	1	NM_198904.4	ENSP00000491909.2		P18507-2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000401

AC:

AN:

249666

AF XY:

0.00000741

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000887

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000275

AC:

AN:

1452292

Hom.:

Cov.:

AF XY:

0.00000415

AC XY:

AN XY:

723148

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33248

American (AMR)

AF:

0.00

AC:

AN:

44550

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26010

East Asian (EAS)

AF:

0.00

AC:

AN:

39444

South Asian (SAS)

AF:

0.00

AC:

AN:

86002

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53276

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5734

European-Non Finnish (NFE)

AF:

0.00000362

AC:

AN:

1104066

Other (OTH)

AF:

0.00

AC:

AN:

59962

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

Age Distribution

Exome Het

Variant carriers

<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.:

Alfa

AF:

0.000111

Hom.:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:6Uncertain:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Febrile seizures, familial, 8

Pathogenic:2Uncertain:1

Apr 13, 2023

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Mar 25, 2024

Genomic Medicine Center of Excellence, King Faisal Specialist Hospital and Research Centre

Significance:Uncertain significance

Review Status:flagged submission

Collection Method:clinical testing

- -

Apr 01, 2024

3billion

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The variant is observed at an extremely low frequency in the gnomAD v4.0.0 dataset (total allele frequency: <0.001%). Predicted Consequence/Location: Missense variant Functional studies provide supporting evidence of the variant having a damaging effect on the gene or gene product (PMID: 35486215). In silico tool predictions suggest damaging effect of the variant on gene or gene product [REVEL: 0.72 (>=0.6, sensitivity 0.68 and specificity 0.92); 3Cnet: 0.69 (>=0.6, sensitivity 0.72 and precision 0.9)]. Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000379114 /PMID: 33391346).The variant has been observed in multiple (>3) similarly affected unrelated individuals (PMID: 31440721, 33726816, 35486215).A different missense change at the same codon (p.Thr90Arg) has been reported to be associated with GABRG2 -related disorder (PMID: 34095830). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -

EPILEPSY, CHILDHOOD ABSENCE, SUSCEPTIBILITY TO, 2;C1969810:Febrile seizures, familial, 8

Pathogenic:1

Feb 29, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 90 of the GABRG2 protein (p.Thr90Met). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This missense change has been observed in individual(s) with clinical features of GABRG2-related conditions (PMID: 33391346; Invitae). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 379114). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt GABRG2 protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -

Autosomal dominant nocturnal frontal lobe epilepsy

Pathogenic:1

Feb 09, 2022

Wen Jiang Lab, Comprehensive Epilepsy Center, Xijing Hospital

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing;in vitro

- -

Generalized epilepsy with febrile seizures plus 3;C1969810:Febrile seizures, familial, 8;C5193074:Developmental and epileptic encephalopathy, 74

Pathogenic:1

Jan 08, 2025

Department of Neurology, Zibo Changguo Hospital

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

PS2, PM1, PM5, PM2_Supporting, PP3 -

not provided

Pathogenic:1

Apr 18, 2025

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Published functional studies demonstrate that this variant significantly impairs cell trafficking and causes GABRG2 subunits to be retained in the endoplasmic reticulum, resulting in decreased surface expression and reduced peak currents (PMID: 35486215); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 33726816, 34095830, 35605087, 31440721, 35359574, 35486215, 33391346) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.74

BayesDel_addAF

Pathogenic

0.42

BayesDel_noAF

Pathogenic

0.36

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.84

.;.;.;D;.;.;.;.;.;.;.

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.96

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.98

D;D;D;D;D;D;D;D;D;D;D

M_CAP

Pathogenic

0.37

MetaRNN

Pathogenic

0.89

D;D;D;D;D;D;D;D;D;D;D

MetaSVM

Uncertain

0.61

MutationAssessor

Pathogenic

3.2

.;M;.;M;.;.;.;.;M;.;.

PhyloP100

7.5

PrimateAI

Uncertain

0.77

PROVEAN

Pathogenic

-4.9

.;.;.;.;.;.;.;.;D;D;.

REVEL

Pathogenic

0.72

Sift

Pathogenic

0.0

.;.;.;.;.;.;.;.;D;D;.

Sift4G

Pathogenic

0.0010

.;.;.;.;.;.;.;.;D;D;.

Polyphen

1.0

.;D;.;D;.;.;.;.;.;.;.

Vest4

0.86, 0.87

MutPred

0.56

.;Gain of ubiquitination at K88 (P = 0.1797);.;Gain of ubiquitination at K88 (P = 0.1797);.;Gain of ubiquitination at K88 (P = 0.1797);.;Gain of ubiquitination at K88 (P = 0.1797);Gain of ubiquitination at K88 (P = 0.1797);Gain of ubiquitination at K88 (P = 0.1797);Gain of ubiquitination at K88 (P = 0.1797);

MVP

0.89

MPC

2.6

ClinPred

1.0

GERP RS

6.1

Varity_R

0.85

gMVP

0.85

Mutation Taster

=172/128

disease causing (ClinVar)

(source)

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

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over