chr20-33412789-G-T

Variant names:

• chr20-33412789-G-T
• rs780688953
• NM_003098.3:c.702-7C>A

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 2P and 6B. PM2 BP4_Strong BP6_Moderate

The NM_003098.3(SNTA1):​c.702-7C>A variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000693 in 1,442,348 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: SNTA1 NM_003098.3 splice_region, intron
• Scores: Splicing: ADA: 0.1794
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 1.77
• 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

LOC124904889 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.6).
• BP6: Variant 20-33412789-G-T is Benign according to our data. Variant chr20-33412789-G-T is described in ClinVar as Likely_benign. ClinVar VariationId is 1016808.Status of the report is criteria_provided_single_submitter, 1 stars.

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SNTA1	NM_003098.3	MANE Select	c.702-7C>A		splice_region intron	N/A	NP_003089.1
	SNTA1	NM_001424413.1		c.702-7C>A		splice_region intron	N/A	NP_001411342.1
	SNTA1	NM_001424414.1		c.702-7C>A		splice_region intron	N/A	NP_001411343.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SNTA1	ENST00000217381.3	TSL:1 MANE Select	c.702-7C>A		splice_region intron	N/A	ENSP00000217381.2
	ENSG00000288878	ENST00000785672.1		n.224+2555G>T		intron	N/A

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.93e-7 AC: 1 AN: 1442348 Hom.: 0 Cov.: 31 AF XY: 0.00000139 AC XY: 1 AN XY: 717292

African (AFR) AF: 0.00 AC: 0 AN: 33010

American (AMR) AF: 0.00 AC: 0 AN: 43336

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25764

East Asian (EAS) AF: 0.00 AC: 0 AN: 39072

South Asian (SAS) AF: 0.00 AC: 0 AN: 84348

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 50046

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5750

European-Non Finnish (NFE) AF: 9.08e-7 AC: 1 AN: 1101208

Other (OTH) AF: 0.00 AC: 0 AN: 59814

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Long QT syndrome Benign:1

Jul 26, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.60
CADD	Benign	14
DANN	Benign	0.79
PhyloP100		1.8

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.18
dbscSNV1_RF	Benign	0.20
SpliceAI score (max)		0.010		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: rs780688953; hg19: chr20-32000595;