NM_020988.3:c.828C>G

Variant names:

• chr16-56351488-C-G
• NM_020988.3:c.828C>G
• GNAO1 p.Gly276Gly

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_020988.3(GNAO1):​c.828C>G​(p.Gly276Gly) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. G276G) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: GNAO1 NM_020988.3 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -4.97
• 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), Ambry Genetics, G2P
• genetic developmental and epileptic encephalopathy

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

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

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

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.6).
• BP7: Synonymous conserved (PhyloP=-4.97 with no splicing effect.

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.828C>G	p.Gly276Gly	synonymous	Exon 7 of 9	NP_066268.1	P09471-1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GNAO1	ENST00000262493.12	TSL:1 MANE Select	c.828C>G	p.Gly276Gly	synonymous	Exon 7 of 9	ENSP00000262493.6	P09471-1
	GNAO1	ENST00000638705.1	TSL:1	c.828C>G	p.Gly276Gly	synonymous	Exon 7 of 8	ENSP00000491223.1	P09471-1
	GNAO1	ENST00000873096.1		c.852C>G	p.Gly284Gly	synonymous	Exon 7 of 9	ENSP00000543155.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.60
CADD	Benign	0.85
DANN	Benign	0.71
PhyloP100		-5.0

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr16-56385400;