15-26567650-G-T

Variant names:

• chr15-26567650-G-T
• NM_000814.6:c.766C>A

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PM5 PP2 PP3_Moderate

The NM_000814.6(GABRB3):​c.766C>A​(p.Leu256Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,798 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L256Q) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: GABRB3 NM_000814.6 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 8.01

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr15-26567649-A-T is described in Lovd as [Pathogenic].
• PP2: Missense variant in the GABRB3 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 56 curated pathogenic missense variants (we use a threshold of 10). The gene has 26 curated benign missense variants. Gene score misZ: 3.3856 (above the threshold of 3.09). Trascript score misZ: 4.4544 (above the threshold of 3.09). GenCC associations: The gene is linked to childhood absence epilepsy, developmental and epileptic encephalopathy, 43, developmental and epileptic encephalopathy, Lennox-Gastaut syndrome, epilepsy, childhood absence, susceptibility to, 5.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.896

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GABRB3	NM_000814.6	c.766C>A	p.Leu256Met	missense_variant	Exon 7 of 9	ENST00000311550.10	NP_000805.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GABRB3	ENST00000311550.10	c.766C>A	p.Leu256Met	missense_variant	Exon 7 of 9	1	NM_000814.6	ENSP00000308725.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461798 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727204

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.84
BayesDel_addAF	Pathogenic	0.29	D
BayesDel_noAF	Pathogenic	0.18
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.57	.;D;.;.;.;.;.;.;.
Eigen	Uncertain	0.66
Eigen_PC	Uncertain	0.64
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.76	.;T;T;T;T;.;T;T;.
M_CAP	Uncertain	0.20	D
MetaRNN	Pathogenic	0.90	D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.54	D
MutationAssessor	Uncertain	2.6	.;M;.;.;M;.;.;.;.
PrimateAI	Pathogenic	0.90	D
PROVEAN	Benign	-1.9	.;N;.;N;N;.;.;N;N
REVEL	Pathogenic	0.66
Sift	Uncertain	0.0060	.;D;.;D;D;.;.;D;D
Sift4G	Uncertain	0.0020	D;D;D;D;D;.;.;D;D
Polyphen		1.0, 1.0	.;D;.;D;D;.;.;.;.
Vest4		0.56
MutPred		0.72		.;.;.;Loss of catalytic residue at L312 (P = 0.0012);.;.;.;.;.;
MVP		0.85
MPC		2.4
ClinPred		0.85	D
GERP RS		6.1
Varity_R		0.73
gMVP		0.81

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr15-26812797;