chr16-56276021-C-T

Variant names:

• chr16-56276021-C-T
• rs756947463
• NM_020988.3:c.252C>T

Variant summary

Our verdict is Benign. The variant received -15 ACMG points: 0P and 15B. BP4_Moderate BP6_Very_Strong BP7 BS2

The NM_020988.3(GNAO1):​c.252C>T​(p.Ile84Ile) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000155 in 1,613,952 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.000026 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000014 (0 hom.)
• Consequence: GNAO1 NM_020988.3 synonymous
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:2
• Conservation: PhyloP100: 0.110
• Publications: 2 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: Benign. The variant received -15 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.24).
• BP6: Variant 16-56276021-C-T is Benign according to our data. Variant chr16-56276021-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 530552.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=0.11 with no splicing effect.
• BS2: High AC in GnomAdExome4 at 21 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GNAO1	NM_020988.3	c.252C>T	p.Ile84Ile	synonymous_variant	Exon 3 of 9	ENST00000262493.12	NP_066268.1
GNAO1	NM_138736.3	c.252C>T	p.Ile84Ile	synonymous_variant	Exon 3 of 8		NP_620073.2
GNAO1	XM_011523003.4	c.126C>T	p.Ile42Ile	synonymous_variant	Exon 3 of 9		XP_011521305.1
GNAO1	XR_007064866.1	n.999C>T		non_coding_transcript_exon_variant	Exon 3 of 9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GNAO1	ENST00000262493.12	c.252C>T	p.Ile84Ile	synonymous_variant	Exon 3 of 9	1	NM_020988.3	ENSP00000262493.6

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152156 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000199 AC: 5 AN: 251374 AF XY: 0.0000147

Gnomad AFR exome AF: 0.0000615

Gnomad AMR exome AF: 0.0000578

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000144 AC: 21 AN: 1461678 Hom.: 0 Cov.: 30 AF XY: 0.0000110 AC XY: 8 AN XY: 727138

African (AFR) AF: 0.0000299 AC: 1 AN: 33478

American (AMR) AF: 0.0000447 AC: 2 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86248

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.0000162 AC: 18 AN: 1111840

Other (OTH) AF: 0.00 AC: 0 AN: 60380

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152274 Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2 AN XY: 74458

African (AFR) AF: 0.0000241 AC: 1 AN: 41554

American (AMR) AF: 0.00 AC: 0 AN: 15302

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5188

South Asian (SAS) AF: 0.00 AC: 0 AN: 4818

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10604

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.0000441 AC: 3 AN: 68020

Other (OTH) AF: 0.00 AC: 0 AN: 2110

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000189

ClinVar

Significance: Likely benign

Submissions summary: Benign:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Developmental and epileptic encephalopathy Benign:1

Oct 31, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Benign:1

Dec 04, 2020

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.24
CADD	Benign	10
DANN	Benign	0.82
PhyloP100		0.11

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: rs756947463; hg19: chr16-56309933; COSMIC: COSV52614473;