rs1057524804

chr12-2581611-C-Achr12-2581611-C-Gchr12-2581611-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_000719.7(CACNA1C):c.1917C>A(p.Asn639Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000705 in 1,417,586 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 nucleotide change resulting in same amino acid change has been previously reported as Uncertain significancein ClinVar. Synonymous variant affecting the same amino acid position (i.e. N639N) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 29)
  • Exomes 𝑓: 7.1e-7 (0 hom.)
• Consequence: CACNA1C NM_000719.7 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 2.24

Genes affected

CACNA1C (HGNC:1390): (calcium voltage-gated channel subunit alpha1 C) This gene encodes an alpha-1 subunit of a voltage-dependent calcium channel. Calcium channels mediate the influx of calcium ions into the cell upon membrane polarization. The alpha-1 subunit consists of 24 transmembrane segments and forms the pore through which ions pass into the cell. The calcium channel consists of a complex of alpha-1, alpha-2/delta, beta, and gamma subunits in a 1:1:1:1 ratio. There are multiple isoforms of each of these proteins, either encoded by different genes or the result of alternative splicing of transcripts. The protein encoded by this gene binds to and is inhibited by dihydropyridine. Alternative splicing results in many transcript variants encoding different proteins. Some of the predicted proteins may not produce functional ion channel subunits. [provided by RefSeq, Oct 2012]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, CACNA1C
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.899

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CACNA1C	NM_000719.7	c.1917C>A	p.Asn639Lys	missense_variant	14/47	ENST00000399655.6
CACNA1C	NM_001167623.2	c.1917C>A	p.Asn639Lys	missense_variant	14/47	ENST00000399603.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CACNA1C	ENST00000399603.6	c.1917C>A	p.Asn639Lys	missense_variant	14/47	5	NM_001167623.2
CACNA1C	ENST00000399655.6	c.1917C>A	p.Asn639Lys	missense_variant	14/47	1	NM_000719.7

Frequencies

GnomAD3 genomes Cov.: 29

GnomAD4 exome AF: 7.05e-7 AC: 1 AN: 1417586 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 700684

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.19e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 29

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Timothy syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Center For Human Genetics And Laboratory Diagnostics, Dr. Klein, Dr. Rost And Colleagues

Feb 02, 2018

- -

Congenital long QT syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Jul 02, 2020

Based on the classification scheme VCGS_Germline_v1.3.3, this variant is classified as VUS-3A. Following criteria are met: 0103 - Loss of function and gain of function are known mechanisms of disease in this gene. (I) 0107 - This gene is associated with autosomal dominant disease. (I) 0200 - Variant is predicted to result in a missense amino acid change from asparagine to lysine (exon 14). (I) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). Note: this region has <30x coverage. (SP) 0502 - Missense variant with conflicting in silico predictions and uninformative conservation. Moderate amino acid change, very high conservation. (I) 0604 - Variant is not located in an established domain, motif, hotspot or informative constraint region. Located in the intracellular region between subunits S4 and S5 of Domain II (PMID: 31004778). (I) 0704 - Another missense variant comparable to the one identified in this case has limited previous evidence for pathogenicity. PMID: 31004778; p.(Asn639Thr) considered likely pathogenic in a female proband, her brother and mother with prolonged QT/?Timothy syndrome. Functional studies of CRISPR/Cas9-edited hiPSC-CMs had indicated an impact on the channel (increased action potential and slower voltage-dependent inactivation). (SP) 0809 - Previous evidence of pathogenicity for this variant is inconclusive. ClinVar: VUS x1 (condition: Timothy syndrome) with an alternative nucleotide change (C>G) causing the same amino acid change also reported as a VUS x2 in ClinVar (conditions: Timothy syndrome, Not provided). (I) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting Pathogenic, (I) – Information, (SB) – Supporting Benign -

Long QT syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 30, 2020

This sequence change replaces asparagine with lysine at codon 639 of the CACNA1C protein (p.Asn639Lys). The asparagine residue is highly conserved and there is a moderate physicochemical difference between asparagine and lysine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with CACNA1C-related conditions. ClinVar contains an entry for this variant (Variation ID: 560694). 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: "Possibly Damaging"; 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
CardioboostArm	Uncertain	0.81
BayesDel_addAF	Pathogenic	0.16	D
BayesDel_noAF	Uncertain	0.0
Cadd	Benign	22
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.67	D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;.;.;.;.;T;.
Eigen	Uncertain	0.24
Eigen_PC	Uncertain	0.28
FATHMM_MKL	Uncertain	0.94	D
M_CAP	Pathogenic	0.65	D
MetaRNN	Pathogenic	0.90	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
PrimateAI	Pathogenic	0.91	D
PROVEAN	Pathogenic	-5.7	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
REVEL	Uncertain	0.61
Sift	Uncertain	0.0010	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
Polyphen		0.42, 0.88, 1.0, 0.85, 0.89, 0.14, 0.85, 0.99, 0.25, 0.16, 0.28	.;B;P;D;P;P;B;B;P;D;B;B;P;B;B;P;.;P;B;.;.;.;B
Vest4		0.83
MutPred		0.64		.;Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);Gain of catalytic residue at N639 (P = 0.0151);
MVP		0.92
MPC		2.3
ClinPred		0.99	D
GERP RS		4.3
gMVP		0.96

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: rs1057524804; hg19: chr12-2690777;