20-33408526-CGG-C

Variant names:

• chr20-33408526-CGG-C
• rs1568745571
• NM_003098.3:c.1497_1498delCC

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_003098.3(SNTA1):​c.1497_1498delCC​(p.Arg500ProfsTer20) variant causes a frameshift change. The variant allele was found at a frequency of 0.000000684 in 1,461,598 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SNTA1 NM_003098.3 frameshift
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 5.49
• Publications: 0 publications found

Genes affected

SNTA1 (HGNC:11167): (syntrophin alpha 1) Syntrophins are cytoplasmic peripheral membrane scaffold proteins that are components of the dystrophin-associated protein complex. This gene is a member of the syntrophin gene family and encodes the most common syntrophin isoform found in cardiac tissues. The N-terminal PDZ domain of this syntrophin protein interacts with the C-terminus of the pore-forming alpha subunit (SCN5A) of the cardiac sodium channel Nav1.5. This protein also associates cardiac sodium channels with the nitric oxide synthase-PMCA4b (plasma membrane Ca-ATPase subtype 4b) complex in cardiomyocytes. This gene is a susceptibility locus for Long-QT syndrome (LQT) - an inherited disorder associated with sudden cardiac death from arrhythmia - and sudden infant death syndrome (SIDS). This protein also associates with dystrophin and dystrophin-related proteins at the neuromuscular junction and alters intracellular calcium ion levels in muscle tissue. [provided by RefSeq, Jan 2013]

SNTA1 Gene-Disease associations (from GenCC):

• long QT syndrome 12

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• long QT syndrome

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ENSG00000288878 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_003098.3. 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
	SNTA1	NM_003098.3	MANE Select	c.1497_1498delCC	p.Arg500ProfsTer20	frameshift	Exon 8 of 8	NP_003089.1	Q13424-1
	SNTA1	NM_001424413.1		c.1494_1495delCC	p.Arg499ProfsTer20	frameshift	Exon 8 of 8	NP_001411342.1
	SNTA1	NM_001424414.1		c.*38_*39delCC		3_prime_UTR	Exon 8 of 8	NP_001411343.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SNTA1	ENST00000217381.3	TSL:1 MANE Select	c.1497_1498delCC	p.Arg500ProfsTer20	frameshift	Exon 8 of 8	ENSP00000217381.2	Q13424-1
	SNTA1	ENST00000953204.1		c.1620_1621delCC	p.Arg541ProfsTer20	frameshift	Exon 9 of 9	ENSP00000623263.1
	SNTA1	ENST00000953205.1		c.1566_1567delCC	p.Arg523ProfsTer20	frameshift	Exon 9 of 9	ENSP00000623264.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461598 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 727110

⚠️ 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: 33476

American (AMR) AF: 0.00 AC: 0 AN: 44724

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: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111752

Other (OTH) AF: 0.00 AC: 0 AN: 60378

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		5.5

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: rs1568745571; hg19: chr20-31996332;