dbSNP rs775895535: GABRA1:p.Tyr252* (chr5-161890950-C-A) – ACMG Classification: Pathogenic (10 pts)

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1PM2

The NM_001127644.2(GABRA1):c.756C>A(p.Tyr252*) variant causes a stop gained 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. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. Y252Y) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

GABRA1
NM_001127644.2 stop_gained

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 0.436

Publications

2 publications found

Variant links:

Genes affected

GABRA1 (HGNC:4075): (gamma-aminobutyric acid type A receptor subunit alpha1) This gene encodes a gamma-aminobutyric acid (GABA) receptor. 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. GABA-A receptors are pentameric, consisting of proteins from several subunit classes: alpha, beta, gamma, delta and rho. Mutations in this gene cause juvenile myoclonic epilepsy and childhood absence epilepsy type 4. Multiple transcript variants encoding the same protein have been identified for this gene. [provided by RefSeq, Jul 2008]

GABRA1 Gene-Disease associations (from GenCC):

developmental and epileptic encephalopathy, 19
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
genetic developmental and epileptic encephalopathy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
epilepsy, idiopathic generalized, susceptibility to, 13
Inheritance: AD Classification: STRONG Submitted by: G2P
Dravet syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
juvenile myoclonic epilepsy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

GABRA1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 10 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;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GABRA1	NM_001127644.2 link	c.756C>A	p.Tyr252*	stop_gained	Exon 8 of 10	ENST00000393943.10	NP_001121116.1	P14867

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GABRA1	ENST00000393943.10 link	c.756C>A	p.Tyr252*	stop_gained	Exon 8 of 10	1	NM_001127644.2	ENSP00000377517.4		P14867

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.0000319

AC:

AN:

250806

AF XY:

0.0000221

show subpopulations

Gnomad AFR exome

AF:

0.000124

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.000139

Gnomad NFE exome

AF:

0.0000265

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.00000137

AC:

AN:

1461032

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726858

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33452

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26120

East Asian (EAS)

AF:

0.00

AC:

AN:

39656

South Asian (SAS)

AF:

0.00

AC:

AN:

86238

European-Finnish (FIN)

AF:

0.0000187

AC:

AN:

53370

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111376

Other (OTH)

AF:

0.0000166

AC:

AN:

60332

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.300

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

ExAC

AF:

0.000379

AC:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.60

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Uncertain

0.25

Eigen_PC

Benign

0.053

FATHMM_MKL

Uncertain

0.85

PhyloP100

0.44

Vest4

0.98, 0.97

GERP RS

-1.0

Mutation Taster

=2/198

disease causing (fs/PTC)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over