rs587777365

Variant names:

• chr5-162093967-C-A
• NM_198904.4:c.247C>A

Your query was ambiguous. Multiple possible variants found:

• chr5-162093967-C-A
• chr5-162093967-C-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5

The NM_198904.4(GABRG2):​c.247C>A​(p.Pro83Thr) variant causes a missense change involving the alteration of a 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P83S) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: GABRG2 NM_198904.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 7.45

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 12 ACMG points.

• PM1: In a topological_domain Extracellular (size 233) in uniprot entity GBRG2_HUMAN there are 9 pathogenic changes around while only 2 benign (82%) in NM_198904.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr5-162093967-C-T is described in Lovd as [Likely_pathogenic].
• PP2: Missense variant in the GABRG2 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 34 curated pathogenic missense variants (we use a threshold of 10). The gene has 21 curated benign missense variants. Gene score misZ: 2.9939 (below the threshold of 3.09). Trascript score misZ: 3.9213 (above the threshold of 3.09). GenCC associations: The gene is linked to epilepsy, Dravet syndrome, undetermined early-onset epileptic encephalopathy, generalized epilepsy with febrile seizures plus, developmental and epileptic encephalopathy, 74, febrile seizures, familial, 8, childhood epilepsy with centrotemporal spikes.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.991
• PP5: Variant 5-162093967-C-A is Pathogenic according to our data. Variant chr5-162093967-C-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 1709680.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GABRG2	NM_198904.4	c.247C>A	p.Pro83Thr	missense_variant	Exon 2 of 10	ENST00000639213.2	NP_944494.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GABRG2	ENST00000639213.2	c.247C>A	p.Pro83Thr	missense_variant	Exon 2 of 10	1	NM_198904.4	ENSP00000491909.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

EPILEPSY, CHILDHOOD ABSENCE, SUSCEPTIBILITY TO, 2;C1969810:Febrile seizures, familial, 8 Pathogenic:1

Dec 13, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces proline, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 83 of the GABRG2 protein (p.Pro83Thr). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with GABRG2-related conditions (Invitae). ClinVar contains an entry for this variant (Variation ID: 1709680). 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%. This variant disrupts the p.Pro83 amino acid residue in GABRG2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 21714819). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Febrile seizures, familial, 8 Uncertain:1

Aug 24, 2021

MGZ Medical Genetics Center

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.92	.;.;.;D;.;.;.;.;.;.;.
Eigen	Pathogenic	0.99
Eigen_PC	Pathogenic	0.94
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	1.0	D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.53	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.9	.;H;.;H;.;.;.;.;H;.;.
PrimateAI	Pathogenic	0.82	D
PROVEAN	Pathogenic	-6.5	.;.;.;.;.;.;.;.;D;D;.
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	.;.;.;.;.;.;.;.;D;D;.
Sift4G	Pathogenic	0.0010	.;.;.;.;.;.;.;.;D;D;.
Polyphen		1.0	.;D;.;D;.;.;.;.;.;.;.
Vest4		0.94
MutPred		0.95		.;Loss of stability (P = 0.02);.;Loss of stability (P = 0.02);.;Loss of stability (P = 0.02);.;Loss of stability (P = 0.02);Loss of stability (P = 0.02);Loss of stability (P = 0.02);Loss of stability (P = 0.02);
MVP		0.98
MPC		2.7
ClinPred		1.0	D
GERP RS		5.8
Varity_R		0.96
gMVP		0.97

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr5-161520973;