rs952757731

Positions:

• chr19-13506196-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_001127222.2(CACNA1A):​c.29C>T​(p.Ala10Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000334 in 1,498,646 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 30)
  • Exomes 𝑓: 0.0000015 (0 hom.)
• Consequence: CACNA1A NM_001127222.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 2.33

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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, CACNA1A
• BP4: Computational evidence support a benign effect (MetaRNN=0.3117051).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CACNA1A	NM_001127222.2	c.29C>T	p.Ala10Val	missense_variant	1/47	ENST00000360228.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CACNA1A	ENST00000360228.11	c.29C>T	p.Ala10Val	missense_variant	1/47	1	NM_001127222.2

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152150 Hom.: 0 Cov.: 30

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000196

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000149 AC: 2 AN: 1346496 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 661814

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000370

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: 0.00

Gnomad4 OTH exome AF: 0.0000179

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152150 Hom.: 0 Cov.: 30 AF XY: 0.0000135 AC XY: 1 AN XY: 74312

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.000196

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000604

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 02, 2023

This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 10 of the CACNA1A protein (p.Ala10Val). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with CACNA1A-related conditions. ClinVar contains an entry for this variant (Variation ID: 422558). 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 with a negative predictive value of 95%. 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. -

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

May 01, 2023

The c.29C>T (p.A10V) alteration is located in exon 1 (coding exon 1) of the CACNA1A gene. This alteration results from a C to T substitution at nucleotide position 29, causing the alanine (A) at amino acid position 10 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jun 12, 2017

The A10V variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. The A10V variant is not observed in large population cohorts; however, limited data are available (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). The A10V variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties, and this substitution occurs at a position that is not conserved. However, in silico analysis is inconsistent in its predictions as to whether or not the variant is damaging to the protein structure/function. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic variant or a rare benign variant. -

Developmental and epileptic encephalopathy, 42 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

New York Genome Center

Mar 05, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.25
BayesDel_addAF	Uncertain	0.054	T
BayesDel_noAF	Benign	-0.16
CADD	Benign	23
DANN	Uncertain	0.98
Eigen	Benign	-0.37
Eigen_PC	Benign	-0.37
FATHMM_MKL	Benign	0.66	D
LIST_S2	Uncertain	0.90	D;D;D;D;D;D;D;D;.;D;D;D;D;D;D
M_CAP	Pathogenic	0.94	D
MetaRNN	Benign	0.31	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	0.028	D
MutationTaster	Benign	0.95	N;N;N
PrimateAI	Pathogenic	0.90	D
Sift4G	Uncertain	0.032	D;D;.;.;.;.;.;.;.;.;.;T;.;.;.
Polyphen		0.041	.;B;.;.;.;.;.;.;.;.;.;.;.;.;.
Vest4		0.16
MutPred		0.24		Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);
MVP		0.87
MPC		1.9
ClinPred		0.50	D
GERP RS		1.7
Varity_R		0.075
gMVP		0.55

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

Publications

LitVar

Other links and lift over

dbSNP: rs952757731; hg19: chr19-13617010;