16-56192353-G-C

Variant names:

• chr16-56192353-G-C
• rs886041715
• NM_020988.3:c.118G>C

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP3_Strong PP5

The NM_020988.3(GNAO1):​c.118G>C​(p.Gly40Arg) variant causes a missense, splice region 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. 16/24 in silico tools predict a damaging outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely pathogenic in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G40A) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: GNAO1 NM_020988.3 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:5 U:1
• Conservation: PhyloP100: 9.59
• Publications: 23 publications found

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-DT (HGNC:27543): (GNAO1 divergent transcript)

ACMG classification

Our verdict: Pathogenic. The variant received 11 ACMG points.

• PM1: In a hotspot region, there are 10 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_020988.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr16-56192574-G-C is described in ClinVar as Pathogenic. ClinVar VariationId is 1802972.Status of the report is no_assertion_criteria_provided, 0 stars.
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.
• PP5: Variant 16-56192353-G-C is Pathogenic according to our data. Variant chr16-56192353-G-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 287466.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_020988.3. 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
	GNAO1	NM_020988.3	MANE Select	c.118G>C	p.Gly40Arg	missense splice_region	Exon 1 of 9	NP_066268.1	P09471-1
	GNAO1	NM_138736.3		c.118G>C	p.Gly40Arg	missense splice_region	Exon 1 of 8	NP_620073.2	P09471-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GNAO1	ENST00000262493.12	TSL:1 MANE Select	c.118G>C	p.Gly40Arg	missense splice_region	Exon 1 of 9	ENSP00000262493.6	P09471-1
	GNAO1	ENST00000262494.13	TSL:1	c.118G>C	p.Gly40Arg	missense splice_region	Exon 1 of 8	ENSP00000262494.7	P09471-2
	GNAO1	ENST00000638705.1	TSL:1	c.118G>C	p.Gly40Arg	missense splice_region	Exon 1 of 8	ENSP00000491223.1	P09471-1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 25

GnomAD4 genome Cov.: 31

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
2	-	-	Epileptic encephalopathy (2)
1	1	-	not provided (2)
1	-	-	Developmental and epileptic encephalopathy (1)
1	-	-	Developmental and epileptic encephalopathy, 17 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	34
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.95	D
Eigen	Pathogenic	0.93
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.91	D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.98	D
MutationAssessor	Pathogenic	4.5	H
PhyloP100		9.6
PrimateAI	Pathogenic	0.92	D
PROVEAN	Pathogenic	-6.4	D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.95
MutPred		0.90		Gain of MoRF binding (P = 0.0073)
MVP		0.99
MPC		2.9
ClinPred		1.0	D
GERP RS		4.8
PromoterAI		-0.36	Neutral
Varity_R		0.97
gMVP		1.0
Mutation Taster		=4/96	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.030		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: rs886041715; hg19: chr16-56226265;