15-26567633-C-G

Variant names:

• chr15-26567633-C-G
• NM_000814.6:c.783G>C
• GABRB3 p.Ser261Ser

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_000814.6(GABRB3):​c.783G>C​(p.Ser261Ser) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign 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. S261S) has been classified as Benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: GABRB3 NM_000814.6 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -1.47
• Publications: 0 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_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.89).
• BP7: Synonymous conserved (PhyloP=-1.47 with no splicing effect.

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GABRB3	NM_000814.6	MANE Select	c.783G>C	p.Ser261Ser	synonymous	Exon 7 of 9	NP_000805.1	P28472-1
	GABRB3	NM_021912.5		c.783G>C	p.Ser261Ser	synonymous	Exon 7 of 9	NP_068712.1	X5DQY4
	GABRB3	NM_001191321.3		c.570G>C	p.Ser190Ser	synonymous	Exon 5 of 7	NP_001178250.1	P28472-3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GABRB3	ENST00000311550.10	TSL:1 MANE Select	c.783G>C	p.Ser261Ser	synonymous	Exon 7 of 9	ENSP00000308725.5	P28472-1
	GABRB3	ENST00000541819.6	TSL:1	c.951G>C	p.Ser317Ser	synonymous	Exon 8 of 10	ENSP00000442408.2	F5H7N0
	GABRB3	ENST00000299267.9	TSL:1	c.783G>C	p.Ser261Ser	synonymous	Exon 7 of 9	ENSP00000299267.4	P28472-2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.89
CADD	Benign	0.078
DANN	Benign	0.33
PhyloP100		-1.5

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr15-26812780;