1-202602977-GCCC-GCCCCC

Variant names:

• chr1-202602977-G-GCC
• rs55968420
• NM_177402.5:c.465+20_465+21dupGG

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 0P and 0B.

The NM_177402.5(SYT2):​c.465+20_465+21dupGG variant causes a intron change involving the alteration of a non-conserved nucleotide. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 0)
  • Exomes 𝑓: 0.0000014 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: SYT2 NM_177402.5 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.00
• Publications: 4 publications found

Genes affected

SYT2 (HGNC:11510): (synaptotagmin 2) This gene encodes a synaptic vesicle membrane protein. The encoded protein is thought to function as a calcium sensor in vesicular trafficking and exocytosis. Mutations in this gene are associated with myasthenic syndrome, presynaptic, congenital, with or without motor neuropathy. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Oct 2014]

SYT2 Gene-Disease associations (from GenCC):

• congenital myasthenic syndrome 7

  Inheritance: AD, AR Classification: STRONG, MODERATE Submitted by: ClinGen, Ambry Genetics, Labcorp Genetics (formerly Invitae), PanelApp Australia, Genomics England PanelApp
• presynaptic congenital myasthenic syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SYT2	NM_177402.5	c.465+20_465+21dupGG		intron_variant	Intron 4 of 8	ENST00000367268.5	NP_796376.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SYT2	ENST00000367268.5	c.465+21_465+22insGG		intron_variant	Intron 4 of 8	1	NM_177402.5	ENSP00000356237.4
SYT2	ENST00000367267.5	c.465+21_465+22insGG		intron_variant	Intron 4 of 8	2		ENSP00000356236.1

Frequencies

GnomAD3 genomes Cov.: 0

GnomAD2 exomes AF: 0.00000412 AC: 1 AN: 242710 AF XY: 0.00000763

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 Data not reliable, filtered out with message: AS_VQSR AF: 0.00000139 AC: 2 AN: 1435446 Hom.: 0 Cov.: 0 AF XY: 0.00000281 AC XY: 2 AN XY: 711376

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

African (AFR) AF: 0.00 AC: 0 AN: 32758

American (AMR) AF: 0.00 AC: 0 AN: 43246

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25084

East Asian (EAS) AF: 0.00 AC: 0 AN: 39008

South Asian (SAS) AF: 0.0000241 AC: 2 AN: 82958

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5638

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1095298

Other (OTH) AF: 0.00 AC: 0 AN: 59038

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0000812204), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 0

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		0.0

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs55968420; hg19: chr1-202572105;