Genetic Variant GABRA1:c.857-8C>T (chr5-161895658-C-T) – ACMG Classification: Likely_benign (-6 pts)

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 0P and 6B. BP4_StrongBP6_Moderate

The NM_001127644.2(GABRA1):c.857-8C>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★).

Frequency

Genomes: 𝑓 0.00014 ( 0 hom., cov: 31)

Exomes 𝑓: 0.00013 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

GABRA1
NM_001127644.2 splice_region, intron

Scores

Splicing: ADA: 0.0003600

Clinical Significance

Likely benign criteria provided, single submitter B:1

Conservation

PhyloP100: -0.150

Publications

0 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: Likely_benign. The variant received -6 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.67).

BP6

Variant 5-161895658-C-T is Benign according to our data. Variant chr5-161895658-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 468881.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GABRA1	NM_001127644.2 link	c.857-8C>T		splice_region_variant, intron_variant	Intron 8 of 9	ENST00000393943.10	NP_001121116.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GABRA1	ENST00000393943.10 link	c.857-8C>T		splice_region_variant, intron_variant	Intron 8 of 9	1	NM_001127644.2	ENSP00000377517.4

Frequencies

GnomAD3 genomes

AF:

0.000141

AC:

AN:

148610

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000247

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.000944

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000164

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000694

AC:

163

AN:

234864

AF XY:

0.000630

show subpopulations

Gnomad AFR exome

AF:

0.000983

Gnomad AMR exome

AF:

0.0000618

Gnomad ASJ exome

AF:

0.00115

Gnomad EAS exome

AF:

0.000117

Gnomad FIN exome

AF:

0.000940

Gnomad NFE exome

AF:

0.000940

Gnomad OTH exome

AF:

0.00175

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.000131

AC:

189

AN:

1441862

Hom.:

Cov.:

AF XY:

0.000125

AC XY:

AN XY:

717316

show subpopulations

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

African (AFR)

AF:

0.000799

AC:

AN:

32536

American (AMR)

AF:

0.000213

AC:

AN:

42348

Ashkenazi Jewish (ASJ)

AF:

0.000350

AC:

AN:

25734

East Asian (EAS)

AF:

0.0000508

AC:

AN:

39354

South Asian (SAS)

AF:

0.0000236

AC:

AN:

84856

European-Finnish (FIN)

AF:

0.000271

AC:

AN:

51584

Middle Eastern (MID)

AF:

0.000530

AC:

AN:

5664

European-Non Finnish (NFE)

AF:

0.0000982

AC:

108

AN:

1100196

Other (OTH)

AF:

0.000269

AC:

AN:

59590

⚠️ 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: 0.259

Heterozygous variant carriers

106

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

Data not reliable, filtered out with message: AS_VQSR

AF:

0.000141

AC:

AN:

148610

Hom.:

Cov.:

AF XY:

0.000180

AC XY:

AN XY:

72322

show subpopulations

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

African (AFR)

AF:

0.0000247

AC:

AN:

40462

American (AMR)

AF:

0.00

AC:

AN:

15060

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3440

East Asian (EAS)

AF:

0.00

AC:

AN:

5086

South Asian (SAS)

AF:

0.00

AC:

AN:

4740

European-Finnish (FIN)

AF:

0.000944

AC:

AN:

9534

Middle Eastern (MID)

AF:

0.00

AC:

AN:

312

European-Non Finnish (NFE)

AF:

0.000164

AC:

AN:

67024

Other (OTH)

AF:

0.00

AC:

AN:

2050

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 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: 0.270

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.0124

Hom.:

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Idiopathic generalized epilepsy;C1970160:Epilepsy, childhood absence 4;C4013473:Epilepsy, idiopathic generalized, susceptibility to, 13

Benign:1

Jan 06, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.67

CADD

Benign

3.2

(source)

DANN

Benign

0.45

PhyloP100

-0.15

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.00036

dbscSNV1_RF

Benign

0.022

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

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over