16-56336744-G-C

Variant names:

• chr16-56336744-G-C
• rs587777057
• NM_020988.3:c.607G>C

Variant summary

Our verdict is Pathogenic. The variant received 20 ACMG points: 20P and 0B. PS1_Very_Strong PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_020988.3(GNAO1):​c.607G>C​(p.Gly203Arg) 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. 14/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Pathogenic in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G203E) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 34)
• Consequence: GNAO1 NM_020988.3 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.99
• Publications: 54 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 20 ACMG points.

• PS1: Transcript NM_020988.3 (GNAO1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PM1: In a hotspot region, there are 16 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 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 chr16-56336745-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 1319183.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989
• PP5: Variant 16-56336744-G-C is Pathogenic according to our data. Variant chr16-56336744-G-C is described in ClinVar as Pathogenic. ClinVar VariationId is 803257.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GNAO1	NM_020988.3	c.607G>C	p.Gly203Arg	missense_variant	Exon 6 of 9	ENST00000262493.12	NP_066268.1
GNAO1	NM_138736.3	c.607G>C	p.Gly203Arg	missense_variant	Exon 6 of 8		NP_620073.2
GNAO1	XM_011523003.4	c.481G>C	p.Gly161Arg	missense_variant	Exon 6 of 9		XP_011521305.1
GNAO1	XR_007064866.1	n.1354G>C		non_coding_transcript_exon_variant	Exon 6 of 9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GNAO1	ENST00000262493.12	c.607G>C	p.Gly203Arg	missense_variant	Exon 6 of 9	1	NM_020988.3	ENSP00000262493.6

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 34

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Developmental and epileptic encephalopathy, 17 Pathogenic:1

May 28, 2019

Mendelics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.95	D;D;.;.
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.98
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.99	.;D;D;D
M_CAP	Pathogenic	0.72	D
MetaRNN	Pathogenic	0.99	D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.1	H;H;H;.
PhyloP100		10
PrimateAI	Pathogenic	0.94	D
PROVEAN	Pathogenic	-7.6	D;.;D;.
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D;.;D;.
Sift4G	Pathogenic	0.0	D;.;D;.
Polyphen		1.0	D;D;D;.
Vest4		0.90
MutPred		0.93		Gain of MoRF binding (P = 0.0199);Gain of MoRF binding (P = 0.0199);Gain of MoRF binding (P = 0.0199);.;
MVP		0.95
MPC		2.9
ClinPred		1.0	D
GERP RS		5.3
PromoterAI		-0.050	Neutral
Varity_R		0.96
gMVP		1.0
Mutation Taster		=0/100	disease causing (ClinVar)

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: rs587777057; hg19: chr16-56370656;