rs1554098235

Variant names:

• chr5-162104026-G-A
• rs1554098235
• NM_198904.4:c.769G>A

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PS3 PM2 PP3_Strong PP5_Very_Strong

The NM_198904.4(GABRG2):​c.769G>A​(p.Gly257Arg) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,646 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 17/26 in silico tools predict a damaging outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV001576904: Experimental studies have shown that this missense change affects GABRG2 function (PMID:25726841)." and additional evidence is available in ClinVar.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: GABRG2 NM_198904.4 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 9.88
• Publications: 4 publications found

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: G2P, Ambry Genetics, 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

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PS3: PS3 evidence extracted from ClinVar submissions: SCV001576904: Experimental studies have shown that this missense change affects GABRG2 function (PMID: 25726841).; SCV005325345: Published functional studies demonstrate a damaging effect on cell surface localization and levels of palmitoylation required for protein trafficking to the cell membrane (PMID: 25726841)
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 5-162104026-G-A is Pathogenic according to our data. Variant chr5-162104026-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 433102.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_198904.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GABRG2	NM_198904.4	MANE Select	c.769G>A	p.Gly257Arg	missense splice_region	Exon 6 of 10	NP_944494.1	P18507-2
	GABRG2	NM_198903.2		c.889G>A	p.Gly297Arg	missense splice_region	Exon 7 of 11	NP_944493.2	P18507-3
	GABRG2	NM_001375343.1		c.889G>A	p.Gly297Arg	missense splice_region	Exon 7 of 10	NP_001362272.1	A0A1X7SBZ8

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GABRG2	ENST00000639213.2	TSL:1 MANE Select	c.769G>A	p.Gly257Arg	missense splice_region	Exon 6 of 10	ENSP00000491909.2	P18507-2
	GABRG2	ENST00000414552.6	TSL:1	c.889G>A	p.Gly297Arg	missense splice_region	Exon 7 of 11	ENSP00000410732.2	P18507-3
	GABRG2	ENST00000639111.2	TSL:1	c.769G>A	p.Gly257Arg	missense splice_region	Exon 6 of 9	ENSP00000492125.2	P18507-1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461646 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727126

African (AFR) AF: 0.00 AC: 0 AN: 33472

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26128

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39630

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53406

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111876

Other (OTH) AF: 0.0000166 AC: 1 AN: 60388

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
1	-	-	EPILEPSY, CHILDHOOD ABSENCE, SUSCEPTIBILITY TO, 2;C1969810:Febrile seizures, familial, 8 (1)
1	-	-	not provided (1)
1	-	-	Self-limited epilepsy with centrotemporal spikes (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.36
CADD	Pathogenic	35
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.88	D
Eigen	Pathogenic	0.91
Eigen_PC	Pathogenic	0.82
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D
M_CAP	Pathogenic	0.43	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Uncertain	0.64	D
MutationAssessor	Pathogenic	3.1	M
PhyloP100		9.9
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-7.6	D
REVEL	Pathogenic	0.88
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0090	D
Polyphen		1.0	D
Vest4		0.87
MutPred		0.88		Loss of ubiquitination at K253 (P = 0.0421)
MVP		0.89
MPC		2.8
ClinPred		1.0	D
GERP RS		5.4
Varity_R		0.92
gMVP		0.97
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.99
SpliceAI score (max)		0.52		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.52		Position offset: 0

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1554098235; hg19: chr5-161531032; COSMIC: COSV62721042; COSMIC: COSV62721042;