chr16-56192319-C-T

Variant names:

• chr16-56192319-C-T
• rs2143270457
• NM_020988.3:c.84C>T

Variant summary

Our verdict is Benign. The variant received -7 ACMG points: 2P and 9B. PM2 BP4_Moderate BP6_Moderate BP7 BS2

The NM_020988.3(GNAO1):​c.84C>T​(p.Ile28Ile) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000343 in 1,457,264 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 0.0000066 (0 hom., cov: 31)
  • Exomes 𝑓: 0.0000034 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: GNAO1 NM_020988.3 synonymous
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 1.11
• 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-DT (HGNC:27543): (GNAO1 divergent transcript)

ACMG classification

Our verdict: Benign. The variant received -7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.32).
• BP6: Variant 16-56192319-C-T is Benign according to our data. Variant chr16-56192319-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 2966319.Status of the report is criteria_provided_single_submitter, 1 stars.
• BP7: Synonymous conserved (PhyloP=1.12 with no splicing effect.
• BS2: High AC in GnomAdExome4 at 5 AD gene.

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.84C>T	p.Ile28Ile	synonymous	Exon 1 of 9	NP_066268.1	P09471-1
	GNAO1	NM_138736.3		c.84C>T	p.Ile28Ile	synonymous	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.84C>T	p.Ile28Ile	synonymous	Exon 1 of 9	ENSP00000262493.6	P09471-1
	GNAO1	ENST00000262494.13	TSL:1	c.84C>T	p.Ile28Ile	synonymous	Exon 1 of 8	ENSP00000262494.7	P09471-2
	GNAO1	ENST00000638705.1	TSL:1	c.84C>T	p.Ile28Ile	synonymous	Exon 1 of 8	ENSP00000491223.1	P09471-1

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152090 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.00

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: 0.00

Gnomad OTH AF: 0.000480

GnomAD4 exome AF: 0.00000343 AC: 5 AN: 1457264 Hom.: 0 Cov.: 29 AF XY: 0.00000552 AC XY: 4 AN XY: 725194

African (AFR) AF: 0.00 AC: 0 AN: 33412

American (AMR) AF: 0.00 AC: 0 AN: 44708

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26108

East Asian (EAS) AF: 0.00 AC: 0 AN: 39682

South Asian (SAS) AF: 0.00 AC: 0 AN: 86156

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52508

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5756

European-Non Finnish (NFE) AF: 0.00000451 AC: 5 AN: 1108704

Other (OTH) AF: 0.00 AC: 0 AN: 60230

GnomAD4 genome Data not reliable, filtered out with message: AS_VQSR AF: 0.00000657 AC: 1 AN: 152204 Hom.: 0 Cov.: 31 AF XY: 0.0000134 AC XY: 1 AN XY: 74416

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 41526

American (AMR) AF: 0.00 AC: 0 AN: 15300

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5154

South Asian (SAS) AF: 0.00 AC: 0 AN: 4824

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10608

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68008

Other (OTH) AF: 0.000475 AC: 1 AN: 2106

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

ClinVar

ClinVar submissions

Significance: Likely benign

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	-	1	Developmental and epileptic encephalopathy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.32
CADD	Benign	17
DANN	Benign	0.92
PhyloP100		1.1
PromoterAI		-0.18	Neutral

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: rs2143270457; hg19: chr16-56226231;