rs574805525

Positions:

• chr19-13212506-C-A
• chr19-13212506-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP2

The NM_001127222.2(CACNA1A):​c.6067G>T​(p.Gly2023Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000702 in 1,423,994 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. G2023S) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: CACNA1A NM_001127222.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.821

Genes affected

CACNA1A (HGNC:1388): (calcium voltage-gated channel subunit alpha1 A) Voltage-dependent calcium channels mediate the entry of calcium ions into excitable cells, and are also involved in a variety of calcium-dependent processes, including muscle contraction, hormone or neurotransmitter release, and gene expression. Calcium channels are multisubunit complexes composed of alpha-1, beta, alpha-2/delta, and gamma subunits. The channel activity is directed by the pore-forming alpha-1 subunit, whereas, the others act as auxiliary subunits regulating this activity. The distinctive properties of the calcium channel types are related primarily to the expression of a variety of alpha-1 isoforms, alpha-1A, B, C, D, E, and S. This gene encodes the alpha-1A subunit, which is predominantly expressed in neuronal tissue. Mutations in this gene are associated with 2 neurologic disorders, familial hemiplegic migraine and episodic ataxia 2. This gene also exhibits polymorphic variation due to (CAG)n-repeats. Multiple transcript variants encoding different isoforms have been found for this gene. In one set of transcript variants, the (CAG)n-repeats occur in the 3' UTR, and are not associated with any disease. But in another set of variants, an insertion extends the coding region to include the (CAG)n-repeats which encode a polyglutamine tract. Expansion of the (CAG)n-repeats from the normal 4-18 to 21-33 in the coding region is associated with spinocerebellar ataxia 6. [provided by RefSeq, Jul 2016]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 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), CACNA1A. . Gene score misZ 5.7845 (greater than the threshold 3.09). Trascript score misZ 3.9354 (greater than threshold 3.09). GenCC has associacion of gene with benign paroxysmal torticollis of infancy, developmental and epileptic encephalopathy, 42, undetermined early-onset epileptic encephalopathy, episodic ataxia type 2, familial or sporadic hemiplegic migraine, spinocerebellar ataxia type 6, Lennox-Gastaut syndrome, migraine, familial hemiplegic, 1.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CACNA1A	NM_001127222.2	c.6067G>T	p.Gly2023Cys	missense_variant	42/47	ENST00000360228.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CACNA1A	ENST00000360228.11	c.6067G>T	p.Gly2023Cys	missense_variant	42/47	1	NM_001127222.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 7.02e-7 AC: 1 AN: 1423994 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 704852

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: 0.0000196

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Episodic ataxia type 2;C4310716:Developmental and epileptic encephalopathy, 42 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 05, 2022

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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt CACNA1A protein function. ClinVar contains an entry for this variant (Variation ID: 839105). This variant has not been reported in the literature in individuals affected with CACNA1A-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glycine, which is neutral and non-polar, with cysteine, which is neutral and slightly polar, at codon 2024 of the CACNA1A protein (p.Gly2024Cys). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.030
CADD	Benign	19
DANN	Uncertain	0.99
DEOGEN2	Benign	0.091	.;.;T;.;.;.;.;.;T;.;.;T;.;.;.;T;.;.
Eigen	Benign	-0.14
Eigen_PC	Benign	-0.25
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Benign	0.84	T;T;T;T;T;T;T;T;T;T;.;T;T;T;T;T;D;T
M_CAP	Pathogenic	0.38	D
MetaRNN	Uncertain	0.56	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.85	D
MutationAssessor	Uncertain	2.5	.;.;.;.;M;.;.;.;.;.;.;.;.;.;M;.;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.51	T
PROVEAN	Pathogenic	-5.8	.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
REVEL	Uncertain	0.52
Sift	Uncertain	0.0030	.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
Sift4G	Uncertain	0.0090	D;D;.;.;.;D;.;.;.;.;.;.;.;.;.;.;.;.
Vest4		0.42
MutPred		0.34		.;.;Loss of glycosylation at S2023 (P = 0.0379);Loss of glycosylation at S2023 (P = 0.0379);Loss of glycosylation at S2023 (P = 0.0379);.;.;Loss of glycosylation at S2023 (P = 0.0379);.;.;.;Loss of glycosylation at S2023 (P = 0.0379);Loss of glycosylation at S2023 (P = 0.0379);.;Loss of glycosylation at S2023 (P = 0.0379);.;.;.;
MVP		0.94
MPC		0.97
ClinPred		0.99	D
GERP RS		1.9
Varity_R		0.65
gMVP		0.67

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: rs574805525; hg19: chr19-13323320;