20-33438877-C-A

Variant names:

• chr20-33438877-C-A
• rs200241523
• NM_003098.3:c.460G>T

Variant summary

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

The NM_003098.3(SNTA1):​c.460G>T​(p.Val154Phe) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,854 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V154I) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SNTA1 NM_003098.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.55
• 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

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SNTA1	NM_003098.3	MANE Select	c.460G>T	p.Val154Phe	missense	Exon 2 of 8	NP_003089.1
	SNTA1	NM_001424413.1		c.460G>T	p.Val154Phe	missense	Exon 2 of 8	NP_001411342.1
	SNTA1	NM_001424414.1		c.460G>T	p.Val154Phe	missense	Exon 2 of 8	NP_001411343.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SNTA1	ENST00000217381.3	TSL:1 MANE Select	c.460G>T	p.Val154Phe	missense	Exon 2 of 8	ENSP00000217381.2
	SNTA1	ENST00000953204.1		c.460G>T	p.Val154Phe	missense	Exon 2 of 9	ENSP00000623263.1
	SNTA1	ENST00000953205.1		c.460G>T	p.Val154Phe	missense	Exon 2 of 9	ENSP00000623264.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461854 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727230

⚠️ 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: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

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

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111988

Other (OTH) AF: 0.00 AC: 0 AN: 60390

⚠️ 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.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.35
BayesDel_addAF	Benign	-0.055	T
BayesDel_noAF	Benign	-0.32
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.32	T
Eigen	Uncertain	0.24
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.85	T
M_CAP	Benign	0.022	T
MetaRNN	Uncertain	0.58	D
MetaSVM	Benign	-0.96	T
MutationAssessor	Benign	1.1	L
PhyloP100		7.6
PrimateAI	Benign	0.43	T
PROVEAN	Benign	-2.1	N
REVEL	Benign	0.15
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0060	D
Polyphen		0.015	B
Vest4		0.71
MutPred		0.48		Loss of disorder (P = 0.1578)
MVP		0.40
MPC		0.89
ClinPred		0.92	D
GERP RS		5.0
Varity_R		0.44
gMVP		0.52
Mutation Taster		=66/34	polymorphism

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: rs200241523; hg19: chr20-32026683;