5-161847213-G-C

Variant names:

• chr5-161847213-G-C
• rs28364635
• ENST00000023897.10:c.-446G>C

Variant summary

Our verdict is Benign. The variant received -12 ACMG points: 0P and 12B. BP4_Strong BS1 BS2

The ENST00000023897.10(GABRA1):​c.-446G>C variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00283 in 152,198 control chromosomes in the GnomAD database, including 11 homozygotes. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: 𝑓 0.0028 (11 hom., cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: GABRA1 ENST00000023897.10 5_prime_UTR
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: -0.617
• Publications: 0 publications found

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

ENSG00000294143 (HGNC:):

ACMG classification

Our verdict: Benign. The variant received -12 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.84).
• BS1: Variant frequency is greater than expected in population eas. GnomAd4 allele frequency = 0.00283 (430/152198) while in subpopulation EAS AF = 0.0547 (282/5160). AF 95% confidence interval is 0.0494. There are 11 homozygotes in GnomAd4. There are 229 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.
• BS2: High AC in GnomAd4 at 430 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GABRA1	NM_000806.5	c.-446G>C		5_prime_UTR_variant	Exon 1 of 11		NP_000797.2
LOC105377696	XR_941158.4	n.74+3307C>G		intron_variant	Intron 1 of 2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GABRA1	ENST00000023897.10	c.-446G>C		5_prime_UTR_variant	Exon 1 of 11	1		ENSP00000023897.6
GABRA1	ENST00000638112.1	c.-501G>C		5_prime_UTR_variant	Exon 1 of 11	5		ENSP00000489839.1
ENSG00000294143	ENST00000721460.1	n.71+3307C>G		intron_variant	Intron 1 of 2

Frequencies

GnomAD3 genomes AF: 0.00283 AC: 430 AN: 152080 Hom.: 10 Cov.: 32

Gnomad AFR AF: 0.00167

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000328

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.0545

Gnomad SAS AF: 0.0108

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000250

Gnomad OTH AF: 0.00239

GnomAD4 exome Data not reliable, filtered out with message: AC0;AS_VQSR AF: 0.00 AC: 0 AN: 12 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 12

African (AFR) AC: 0 AN: 0

American (AMR) AC: 0 AN: 0

Ashkenazi Jewish (ASJ) AC: 0 AN: 0

East Asian (EAS) AC: 0 AN: 0

South Asian (SAS) AC: 0 AN: 0

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 2

Middle Eastern (MID) AC: 0 AN: 0

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 8

Other (OTH) AF: 0.00 AC: 0 AN: 2

GnomAD4 genome AF: 0.00283 AC: 430 AN: 152198 Hom.: 11 Cov.: 32 AF XY: 0.00308 AC XY: 229 AN XY: 74418

African (AFR) AF: 0.00169 AC: 70 AN: 41532

American (AMR) AF: 0.000327 AC: 5 AN: 15286

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.0547 AC: 282 AN: 5160

South Asian (SAS) AF: 0.0106 AC: 51 AN: 4798

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10614

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.000250 AC: 17 AN: 68020

Other (OTH) AF: 0.00237 AC: 5 AN: 2114

Alfa AF: 0.000143 Hom.: 0

Bravo AF: 0.00252

Asia WGS AF: 0.0300 AC: 105 AN: 3478

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Epilepsy, idiopathic generalized, susceptibility to, 13 Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.84
CADD	Benign	0.18
DANN	Benign	0.44
PhyloP100		-0.62
PromoterAI		0.093	Neutral
Mutation Taster		=300/0	polymorphism

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

Other links and lift over

dbSNP: rs28364635; hg19: chr5-161274219;