rs869312939

Positions:

• chr16-56192588-G-C

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PM1 PM2 PP2 PP3_Strong PP5_Very_Strong

The NM_020988.3(GNAO1):​c.133G>C​(p.Gly45Arg) 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. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. G45G) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 26)
• Consequence: GNAO1 NM_020988.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 9.69

Genes affected

GNAO1 (HGNC:4389): (G protein subunit alpha o1) The protein encoded by this gene represents the alpha subunit of the Go heterotrimeric G-protein signal-transducing complex. Defects in this gene are a cause of early-onset epileptic encephalopathy. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Aug 2015]

GNAO1-AS1 (HGNC:24498): (GNAO1 antisense RNA 1)

ACMG classification

Verdict is Pathogenic. Variant got 17 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_020988.3
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), GNAO1. . Gene score misZ 3.1919 (greater than the threshold 3.09). Trascript score misZ 4.549 (greater than threshold 3.09). GenCC has associacion of gene with developmental and epileptic encephalopathy, 17, neurodevelopmental disorder with involuntary movements, developmental and epileptic encephalopathy, movement disorder.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989
• PP5: Variant 16-56192588-G-C is Pathogenic according to our data. Variant chr16-56192588-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 225047.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr16-56192588-G-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GNAO1	NM_020988.3	c.133G>C	p.Gly45Arg	missense_variant	2/9	ENST00000262493.12
GNAO1-AS1	NR_026889.1			downstream_gene_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GNAO1	ENST00000262493.12	c.133G>C	p.Gly45Arg	missense_variant	2/9	1	NM_020988.3	P1
GNAO1-AS1	ENST00000567381.1			downstream_gene_variant

Frequencies

GnomAD3 genomes Cov.: 26

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 26

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

-

Overall WES conclusion for patient, including all identified alterations: POSITIVE: Relevant Alteration(s) Detected -

Early infantile epileptic encephalopathy with suppression bursts Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Aug 27, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	D;.;D;.;T;.
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	.;D;D;D;D;D
M_CAP	Pathogenic	0.88	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D
MetaSVM	Pathogenic	0.98	D
MutationAssessor	Pathogenic	3.8	H;.;H;H;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.92	D
PROVEAN	Pathogenic	-6.4	D;.;.;D;.;.
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;.;.;D;.;.
Sift4G	Pathogenic	0.0	D;.;.;D;D;.
Polyphen		1.0	D;.;D;D;.;.
Vest4		0.95
MutPred		0.93		Loss of ubiquitination at K46 (P = 0.022);Loss of ubiquitination at K46 (P = 0.022);Loss of ubiquitination at K46 (P = 0.022);Loss of ubiquitination at K46 (P = 0.022);Loss of ubiquitination at K46 (P = 0.022);Loss of ubiquitination at K46 (P = 0.022);
MVP		0.99
MPC		2.9
ClinPred		1.0	D
GERP RS		4.7
Varity_R		0.96
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs869312939; hg19: chr16-56226500;