rs749796276

Positions:

• chr1-115727038-G-A
• chr1-115727038-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_001232.4(CASQ2):​c.691C>T​(p.Pro231Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,574 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. P231L) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: CASQ2 NM_001232.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 9.42

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.861

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CASQ2	NM_001232.4	c.691C>T	p.Pro231Ser	missense_variant	6/11	ENST00000261448.6	NP_001223.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CASQ2	ENST00000261448.6	c.691C>T	p.Pro231Ser	missense_variant	6/11	1	NM_001232.4	ENSP00000261448.5
CASQ2	ENST00000488931.2	n.*63C>T		non_coding_transcript_exon_variant	8/13	3		ENSP00000518226.1
CASQ2	ENST00000488931.2	n.*63C>T		3_prime_UTR_variant	8/13	3		ENSP00000518226.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461574 Hom.: 0 Cov.: 33 AF XY: 0.00000275 AC XY: 2 AN XY: 727124

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Catecholaminergic polymorphic ventricular tachycardia 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genome-Nilou Lab

Apr 11, 2023

- -

Catecholaminergic polymorphic ventricular tachycardia 1;C2677794:Catecholaminergic polymorphic ventricular tachycardia 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Sep 13, 2021

- -

Catecholaminergic polymorphic ventricular tachycardia 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 23, 2022

This sequence change replaces proline, which is neutral and non-polar, with serine, which is neutral and polar, at codon 231 of the CASQ2 protein (p.Pro231Ser). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with catecholaminergic polymorphic ventricular tachycardia (PMID: 32693635). ClinVar contains an entry for this variant (Variation ID: 580505). 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: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C25"). 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. -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 19, 2023

The p.P231S variant (also known as c.691C>T), located in coding exon 6 of the CASQ2 gene, results from a C to T substitution at nucleotide position 691. The proline at codon 231 is replaced by serine, an amino acid with similar properties. This alteration has been reported in a catecholaminergic polymorphic ventricular tachycardia (CPVT) cohort; however, clinical details were limited (Ng K et al. Circulation, 2020 Sep;142:932-947). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.52
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Uncertain	0.11
CADD	Pathogenic	28
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.62	D
Eigen	Pathogenic	0.91
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.97	D
M_CAP	Benign	0.063	D
MetaRNN	Pathogenic	0.86	D
MetaSVM	Uncertain	0.16	D
MutationAssessor	Uncertain	2.6	M
PrimateAI	Uncertain	0.56	T
PROVEAN	Pathogenic	-4.8	D
REVEL	Pathogenic	0.77
Sift	Uncertain	0.0040	D
Sift4G	Uncertain	0.015	D
Polyphen		1.0	D
Vest4		0.73
MutPred		0.69		Loss of catalytic residue at N229 (P = 0.067);
MVP		0.98
MPC		0.29
ClinPred		0.99	D
GERP RS		5.8
Varity_R		0.65
gMVP		0.70

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

Publications

LitVar

Other links and lift over

dbSNP: rs749796276; hg19: chr1-116269659;