chr4-46250336-C-T

Position:

• chr4-46250336-C-T

Variant summary

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

The NM_000807.4(GABRA2):​c.1328G>A​(p.Arg443Lys) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: GABRA2 NM_000807.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.17

Genes affected

GABRA2 (HGNC:4076): (gamma-aminobutyric acid type A receptor subunit alpha2) GABA is the major inhibitory neurotransmitter in the mammalian brain where it acts at GABA-A receptors, which are ligand-gated chloride channels. Chloride conductance of these channels can be modulated by agents such as benzodiazepines that bind to the GABA-A receptor. At least 16 distinct subunits of GABA-A receptors have been identified. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Nov 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 in gene, where missense usually causes diseases (based on misZ statistic), GABRA2. . Gene score misZ 3.1277 (greater than the threshold 3.09). Trascript score misZ 3.4041 (greater than threshold 3.09). GenCC has associacion of gene with developmental and epileptic encephalopathy, 78, undetermined early-onset epileptic encephalopathy.
• BP4: Computational evidence support a benign effect (MetaRNN=0.21702495).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GABRA2	NM_000807.4	c.1328G>A	p.Arg443Lys	missense_variant	10/10	ENST00000381620.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GABRA2	ENST00000381620.9	c.1328G>A	p.Arg443Lys	missense_variant	10/10	1	NM_000807.4	P2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 27, 2023

This sequence change replaces arginine, which is basic and polar, with lysine, which is basic and polar, at codon 503 of the GABRA2 protein (p.Arg503Lys). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with GABRA2-related conditions. Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Uncertain	0.11
CADD	Uncertain	24
DANN	Benign	0.96
DEOGEN2	Benign	0.095	T;T;T;T;T;T
Eigen	Benign	0.074
Eigen_PC	Uncertain	0.29
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.95	.;.;.;D;D;D
M_CAP	Benign	0.019	T
MetaRNN	Benign	0.22	T;T;T;T;T;T
MetaSVM	Benign	-0.50	T
MutationAssessor	Benign	0.85	L;L;L;L;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D
PrimateAI	Pathogenic	0.84	D
PROVEAN	Benign	-0.28	N;N;N;N;.;N
REVEL	Uncertain	0.37
Sift	Benign	0.41	T;T;T;T;.;T
Sift4G	Benign	0.76	T;T;T;T;T;T
Polyphen		0.018	B;B;B;B;.;.
Vest4		0.12
MutPred		0.43		Gain of methylation at R443 (P = 0.0138);Gain of methylation at R443 (P = 0.0138);Gain of methylation at R443 (P = 0.0138);Gain of methylation at R443 (P = 0.0138);.;.;
MVP		0.95
MPC		0.28
ClinPred		0.66	D
GERP RS		5.8
Varity_R		0.28
gMVP		0.55

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

LitVar

Other links and lift over

dbSNP: rs200987678; hg19: chr4-46252353; COSMIC: COSV62916606;