12-2668946-T-C

Position:

• chr12-2668946-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP2 PP3_Strong

The NM_000719.7(CACNA1C):​c.4637T>C​(p.Met1546Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 11/19 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CACNA1C NM_000719.7 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.02

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]

CACNA1C-AS2 (HGNC:40118): (CACNA1C antisense RNA 2)

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), CACNA1C. . Gene score misZ 6.4654 (greater than the threshold 3.09). Trascript score misZ 7.2674 (greater than threshold 3.09). GenCC has associacion of gene with intellectual disability, neurodevelopmental disorder with hypotonia, language delay, and skeletal defects with or without seizures, Brugada syndrome, long QT syndrome, short QT syndrome, long qt syndrome 8, Timothy syndrome, Brugada syndrome 3.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.939

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CACNA1C	NM_000719.7	c.4637T>C	p.Met1546Thr	missense_variant	38/47	ENST00000399655.6	NP_000710.5
CACNA1C	NM_001167623.2	c.4637T>C	p.Met1546Thr	missense_variant	38/47	ENST00000399603.6	NP_001161095.1
CACNA1C-AS2	NR_046579.1	n.163A>G		non_coding_transcript_exon_variant	2/2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CACNA1C	ENST00000399603.6	c.4637T>C	p.Met1546Thr	missense_variant	38/47	5	NM_001167623.2	ENSP00000382512
CACNA1C	ENST00000399655.6	c.4637T>C	p.Met1546Thr	missense_variant	38/47	1	NM_000719.7	ENSP00000382563
CACNA1C-AS2	ENST00000545526.1	n.163A>G		non_coding_transcript_exon_variant	2/2	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Long QT syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 23, 2019

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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with CACNA1C-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces methionine with threonine at codon 1546 of the CACNA1C protein (p.Met1546Thr). The methionine residue is highly conserved and there is a moderate physicochemical difference between methionine and threonine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	28
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.79	D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;.;.;.;.;T;.;T
Eigen	Pathogenic	0.77
Eigen_PC	Uncertain	0.65
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.94	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	1.1	D
MutationAssessor	Pathogenic	3.6	.;.;.;.;.;.;.;.;.;.;H;.;.;.;.;.;.;.;.;.;.;.;.
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
PrimateAI	Pathogenic	0.92	D
PROVEAN	Pathogenic	-5.5	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;.
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;.
Sift4G	Pathogenic	0.0	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
Polyphen		0.99, 1.0, 0.90, 1.0, 0.99, 0.98, 0.99, 0.97, 0.92	.;D;D;P;D;D;D;D;D;D;D;D;D;D;D;.;D;D;.;.;.;P;.
Vest4		0.96
MutPred		0.65		.;.;.;.;.;.;.;.;.;.;Gain of catalytic residue at K1589 (P = 0);.;.;.;.;.;.;.;.;.;.;.;.;
MVP		0.97
MPC		2.4
ClinPred		1.0	D
GERP RS		3.7
gMVP		1.0

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: rs2096394299; hg19: chr12-2778112;