chr16-56336741-G-C

Variant names:

• chr16-56336741-G-C
• rs1297388989
• NM_020988.3:c.604G>C

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_020988.3(GNAO1):​c.604G>C​(p.Val202Leu) 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. 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. V202I) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 34)
• Consequence: GNAO1 NM_020988.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.99
• Publications: 0 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 Gene-Disease associations (from GenCC):

• developmental and epileptic encephalopathy, 17

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

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• movement disorder

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen, Illumina
• neurodevelopmental disorder with involuntary movements

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PM1: In a hotspot region, there are 17 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 chr16-56336741-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 545591.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.97

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GNAO1	NM_020988.3	MANE Select	c.604G>C	p.Val202Leu	missense	Exon 6 of 9	NP_066268.1
	GNAO1	NM_138736.3		c.604G>C	p.Val202Leu	missense	Exon 6 of 8	NP_620073.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GNAO1	ENST00000262493.12	TSL:1 MANE Select	c.604G>C	p.Val202Leu	missense	Exon 6 of 9	ENSP00000262493.6
	GNAO1	ENST00000262494.13	TSL:1	c.604G>C	p.Val202Leu	missense	Exon 6 of 8	ENSP00000262494.7
	GNAO1	ENST00000638705.1	TSL:1	c.604G>C	p.Val202Leu	missense	Exon 6 of 8	ENSP00000491223.1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD2 exomes AF: 0.00 AC: 0 AN: 245954 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 34

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.44
CADD	Pathogenic	31
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.85	D
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.45	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Pathogenic	0.98	D
MutationAssessor	Pathogenic	3.5	M
PhyloP100		10
PrimateAI	Pathogenic	0.90	D
PROVEAN	Uncertain	-2.8	D
REVEL	Pathogenic	0.88
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.052	T
Polyphen		1.0	D
Vest4		0.87
MutPred		0.88		Loss of MoRF binding (P = 0.1258)
MVP		0.96
MPC		2.6
ClinPred		1.0	D
GERP RS		5.3
PromoterAI		-0.084	Neutral
Varity_R		0.98
gMVP		0.96

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: rs1297388989; hg19: chr16-56370653;