rs1554100910

Variant names:

• chr5-162149112-C-G
• rs1554100910
• NM_198904.4:c.927C>G

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_198904.4(GABRG2):​c.927C>G​(p.Ile309Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I309T) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: GABRG2 NM_198904.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.493
• Publications: 0 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: Likely_pathogenic. The variant received 6 ACMG points.

• PM1: In a hotspot region, there are 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in NM_198904.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.937

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.927C>G	p.Ile309Met	missense	Exon 8 of 10	NP_944494.1	P18507-2
	GABRG2	NM_198903.2		c.1047C>G	p.Ile349Met	missense	Exon 9 of 11	NP_944493.2	P18507-3
	GABRG2	NM_001375343.1		c.1047C>G	p.Ile349Met	missense	Exon 9 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.927C>G	p.Ile309Met	missense	Exon 8 of 10	ENSP00000491909.2	P18507-2
	GABRG2	ENST00000414552.6	TSL:1	c.1047C>G	p.Ile349Met	missense	Exon 9 of 11	ENSP00000410732.2	P18507-3
	GABRG2	ENST00000639111.2	TSL:1	c.927C>G	p.Ile309Met	missense	Exon 8 of 9	ENSP00000492125.2	P18507-1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	EPILEPSY, CHILDHOOD ABSENCE, SUSCEPTIBILITY TO, 2;C1969810:Febrile seizures, familial, 8 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.33
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.82	D
Eigen	Uncertain	0.50
Eigen_PC	Uncertain	0.41
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Benign	0.78	T
M_CAP	Pathogenic	0.50	D
MetaRNN	Pathogenic	0.94	D
MetaSVM	Uncertain	0.77	D
MutationAssessor	Pathogenic	3.0	M
PhyloP100		0.49
PrimateAI	Pathogenic	0.90	D
PROVEAN	Uncertain	-2.7	D
REVEL	Pathogenic	0.83
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.95
MutPred		0.83		Loss of stability (P = 0.0451)
MVP		0.92
MPC		2.6
ClinPred		0.98	D
GERP RS		2.6
Varity_R		0.90
gMVP		0.93
Mutation Taster		=23/77	disease causing

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

Other links and lift over

dbSNP: rs1554100910; hg19: chr5-161576118;