15-26547853-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_000814.6(GABRB3):c.1362C>G(p.Ile454Met) 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 benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. I454I) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: GABRB3 NM_000814.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.0500

Genes affected

GABRB3 (HGNC:4083): (gamma-aminobutyric acid type A receptor subunit beta3) This gene encodes a member of the ligand-gated ionic channel family. The encoded protein is one the subunits of a multi-subunit chloride channel that serves as the receptor for gamma-aminobutyric acid, a major inhibitory neurotransmitter of the mammalian nervous system. This gene is located on the long arm of chromosome 15 in a cluster with two other genes encoding related subunits of the family. This gene may be associated with the pathogenesis of several disorders including Angelman syndrome, Prader-Willi syndrome, nonsyndromic orofacial clefts, epilepsy and autism. Alternatively spliced transcript variants encoding distinct isoforms have been described. [provided by RefSeq, Jul 2013]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, GABRB3
• BP4: Computational evidence support a benign effect (MetaRNN=0.26114744).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GABRB3	NM_000814.6	c.1362C>G	p.Ile454Met	missense_variant	9/9	ENST00000311550.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GABRB3	ENST00000311550.10	c.1362C>G	p.Ile454Met	missense_variant	9/9	1	NM_000814.6	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Epilepsy, childhood absence, susceptibility to, 1;C2677087:Epilepsy, childhood absence, susceptibility to, 5 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Nov 08, 2022

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. 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 not expected to disrupt GABRB3 protein function. ClinVar contains an entry for this variant (Variation ID: 1372092). This variant has not been reported in the literature in individuals affected with GABRB3-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces isoleucine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 454 of the GABRB3 protein (p.Ile454Met). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.064
BayesDel_addAF	Benign	-0.017	T
BayesDel_noAF	Benign	-0.26
Cadd	Benign	16
Dann	Benign	0.90
Eigen	Benign	-0.36
Eigen_PC	Benign	-0.19
FATHMM_MKL	Benign	0.70	D
M_CAP	Benign	0.018	T
MetaRNN	Benign	0.26	T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.70	T
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Uncertain	0.66	T
Sift4G	Benign	0.59	T;T;T;T;T;.;.;T;T
Polyphen		0.011, 0.18, 0.023	.;B;.;B;B;.;.;.;.
Vest4		0.13
MutPred		0.59		.;.;.;Gain of catalytic residue at I510 (P = 0.1308);.;.;.;.;.;
MVP		0.59
MPC		1.4
ClinPred		0.23	T
GERP RS		2.1
Varity_R		0.11
gMVP		0.83

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: chr15-26793000;