rs1555401442

Variant names:

• chr15-26561171-T-C
• rs1555401442
• NM_000814.6:c.841A>G

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PP3_Strong PP5

The NM_000814.6(GABRB3):​c.841A>G​(p.Thr281Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 33)
• Consequence: GABRB3 NM_000814.6 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:2
• Conservation: PhyloP100: 7.90
• Publications: 2 publications found

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]

GABRB3 Gene-Disease associations (from GenCC):

• developmental and epileptic encephalopathy, 43

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• epilepsy, childhood absence, susceptibility to, 5

  Inheritance: AD, Unknown Classification: DEFINITIVE, LIMITED Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• genetic developmental and epileptic encephalopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• childhood absence epilepsy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Lennox-Gastaut syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000814.6
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.955
• PP5: Variant 15-26561171-T-C is Pathogenic according to our data. Variant chr15-26561171-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 548619.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000814.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GABRB3	NM_000814.6	MANE Select	c.841A>G	p.Thr281Ala	missense	Exon 8 of 9	NP_000805.1
	GABRB3	NM_021912.5		c.841A>G	p.Thr281Ala	missense	Exon 8 of 9	NP_068712.1
	GABRB3	NM_001191321.3		c.628A>G	p.Thr210Ala	missense	Exon 6 of 7	NP_001178250.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GABRB3	ENST00000311550.10	TSL:1 MANE Select	c.841A>G	p.Thr281Ala	missense	Exon 8 of 9	ENSP00000308725.5
	GABRB3	ENST00000541819.6	TSL:1	c.1009A>G	p.Thr337Ala	missense	Exon 9 of 10	ENSP00000442408.2
	GABRB3	ENST00000299267.9	TSL:1	c.841A>G	p.Thr281Ala	missense	Exon 8 of 9	ENSP00000299267.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions as Germline

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	1	-	Developmental and epileptic encephalopathy, 1 (1)
1	-	-	Developmental and epileptic encephalopathy, 43 (1)
-	1	-	Epilepsy, childhood absence, susceptibility to, 1 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.46
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.87	D
Eigen	Pathogenic	0.82
Eigen_PC	Pathogenic	0.73
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.79	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Pathogenic	0.96	D
MutationAssessor	Pathogenic	4.5	H
PhyloP100		7.9
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-4.9	D
REVEL	Pathogenic	0.95
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.93
MutPred		0.78		Loss of glycosylation at T337 (P = 0.0191)
MVP		0.98
MPC		2.2
ClinPred		1.0	D
GERP RS		4.9
Varity_R		0.88
gMVP		0.97
Mutation Taster		=2/98	disease causing

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: rs1555401442; hg19: chr15-26806318;