NM_001232.4:c.23T>C

Variant names:

• chr1-115768519-A-G
• rs1553197935
• NM_001232.4:c.23T>C

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The NM_001232.4(CASQ2):​c.23T>C​(p.Ile8Thr) variant causes a missense change. The variant allele was found at a frequency of 0.000000685 in 1,460,458 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I8V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CASQ2 NM_001232.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.42
• Publications: 0 publications found

Genes affected

CASQ2 (HGNC:1513): (calsequestrin 2) The protein encoded by this gene specifies the cardiac muscle family member of the calsequestrin family. Calsequestrin is localized to the sarcoplasmic reticulum in cardiac and slow skeletal muscle cells. The protein is a calcium binding protein that stores calcium for muscle function. Mutations in this gene cause stress-induced polymorphic ventricular tachycardia, also referred to as catecholaminergic polymorphic ventricular tachycardia 2 (CPVT2), a disease characterized by bidirectional ventricular tachycardia that may lead to cardiac arrest. [provided by RefSeq, Jul 2008]

CASQ2 Gene-Disease associations (from GenCC):

• catecholaminergic polymorphic ventricular tachycardia

  Inheritance: AD, AR Classification: DEFINITIVE, MODERATE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• catecholaminergic polymorphic ventricular tachycardia 2

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P, Genomics England PanelApp
• hypertrophic cardiomyopathy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.36731878).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CASQ2	NM_001232.4	c.23T>C	p.Ile8Thr	missense_variant	Exon 1 of 11	ENST00000261448.6	NP_001223.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CASQ2	ENST00000261448.6	c.23T>C	p.Ile8Thr	missense_variant	Exon 1 of 11	1	NM_001232.4	ENSP00000261448.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460458 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 726636

African (AFR) AF: 0.00 AC: 0 AN: 33456

American (AMR) AF: 0.00 AC: 0 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26126

East Asian (EAS) AF: 0.00 AC: 0 AN: 39670

South Asian (SAS) AF: 0.00 AC: 0 AN: 86238

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: 9.00e-7 AC: 1 AN: 1110726

Other (OTH) AF: 0.00 AC: 0 AN: 60342

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Catecholaminergic polymorphic ventricular tachycardia 1 Uncertain:1

Aug 28, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces isoleucine with threonine at codon 8 of the CASQ2 protein (p.Ile8Thr). The isoleucine residue is weakly conserved and there is a moderate physicochemical difference between isoleucine and threonine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with CASQ2-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.076
BayesDel_addAF	Benign	-0.089	T
BayesDel_noAF	Benign	-0.37
CADD	Benign	22
DANN	Benign	0.97
DEOGEN2	Benign	0.20	T
Eigen	Benign	-0.36
Eigen_PC	Benign	-0.28
FATHMM_MKL	Uncertain	0.87	D
LIST_S2	Benign	0.70	T
M_CAP	Benign	0.032	D
MetaRNN	Benign	0.37	T
MetaSVM	Benign	-0.91	T
MutationAssessor	Benign	0.69	N
PhyloP100		6.4
PrimateAI	Benign	0.34	T
PROVEAN	Benign	-1.5	N
REVEL	Uncertain	0.30
Sift	Benign	0.042	D
Sift4G	Uncertain	0.0050	D
Polyphen		0.0020	B
Vest4		0.34
MutPred		0.72		Loss of stability (P = 0.0406);
MVP		0.94
MPC		0.066
ClinPred		0.49	T
GERP RS		5.5
PromoterAI		0.019	Neutral
Varity_R		0.12
gMVP		0.46
Mutation Taster		=94/6	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
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: rs1553197935; hg19: chr1-116311140;