rs878854144

chr5-162097839-CG-C

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1 PM2 PP3_Moderate PP5_Moderate

The NM_198904.4(GABRG2):c.530del(p.Arg177GlnfsTer6) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: GABRG2 NM_198904.4 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 4.82

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]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 5-162097839-CG-C is Pathogenic according to our data. Variant chr5-162097839-CG-C is described in ClinVar as [Pathogenic]. Clinvar id is 238189.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GABRG2	NM_198904.4	c.530del	p.Arg177GlnfsTer6	frameshift_variant	4/10	ENST00000639213.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GABRG2	ENST00000639213.2	c.530del	p.Arg177GlnfsTer6	frameshift_variant	4/10	1	NM_198904.4	A1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Epilepsy, childhood absence 2;C1969810:Febrile seizures, familial, 8 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jun 13, 2019

This sequence change creates a premature translational stop signal at codon 177 (p.Arg177Glnfs*6). It is expected to result in an absent or disrupted protein product. While this particular variant has not been reported in the literature, truncating variants in GABRG2 are known to be pathogenic (PMID: 18566737). This variant has been observed to segregate with GABRG2-related conditions in a single family in the Invitae database. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.88		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.88		Position offset: -3

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

Publications

LitVar

Other links and lift over

dbSNP: rs878854144; hg19: chr5-161524845;