rs121908215

chr19-13359707-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Moderate PP5_Moderate

The NM_001127222.2(CACNA1A):c.877G>A(p.Gly293Arg) 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. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CACNA1A NM_001127222.2 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:3 O:1
• Conservation: PhyloP100: 7.79

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 Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_001127222.2
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, CACNA1A
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.911
• PP5: Variant 19-13359707-C-T is Pathogenic according to our data. Variant chr19-13359707-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 8496.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CACNA1A	NM_001127222.2	c.877G>A	p.Gly293Arg	missense_variant	6/47	ENST00000360228.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CACNA1A	ENST00000360228.11	c.877G>A	p.Gly293Arg	missense_variant	6/47	1	NM_001127222.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Spinocerebellar ataxia type 6 Pathogenic:1 Other:1

not provided, no classification provided	literature only	UniProtKB/Swiss-Prot	-	- -
Pathogenic, no assertion criteria provided	literature only	OMIM	Jun 28, 2005	- -

Episodic ataxia type 2 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Jun 28, 2005

- -

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

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Sep 13, 2020

This sequence change replaces glycine with arginine at codon 293 of the CACNA1A protein (p.Gly293Arg). The glycine residue is highly conserved and there is a moderate physicochemical difference between glycine and arginine. This variant is not present in population databases (ExAC no frequency). This variant has been observed in individual(s) with clinical features of episodic ataxia type 2 (PMID: 9345107, Invitae). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 8496). Experimental studies have shown that this variant affects CACNA1A protein function (PMID: 11742003, 15985579, 18434528). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.53
Cadd	Pathogenic	26
Dann	Uncertain	1.0
Eigen	Pathogenic	0.80
Eigen_PC	Pathogenic	0.80
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	D;D;D;D;D;D;D;D;.;D;D;D;D;D;D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.91	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationTaster	Benign	1.0	A;A;A
PrimateAI	Pathogenic	0.82	D
Sift4G	Pathogenic	0.0	D;D;.;.;.;.;.;.;.;.;.;D;.;.;.
Polyphen		1.0	.;D;.;.;.;.;.;.;.;.;.;.;.;.;.
Vest4		0.95
MutPred		0.56		Loss of catalytic residue at P289 (P = 0.0966);Loss of catalytic residue at P289 (P = 0.0966);Loss of catalytic residue at P289 (P = 0.0966);Loss of catalytic residue at P289 (P = 0.0966);Loss of catalytic residue at P289 (P = 0.0966);.;Loss of catalytic residue at P289 (P = 0.0966);Loss of catalytic residue at P289 (P = 0.0966);Loss of catalytic residue at P289 (P = 0.0966);Loss of catalytic residue at P289 (P = 0.0966);Loss of catalytic residue at P289 (P = 0.0966);Loss of catalytic residue at P289 (P = 0.0966);Loss of catalytic residue at P289 (P = 0.0966);Loss of catalytic residue at P289 (P = 0.0966);Loss of catalytic residue at P289 (P = 0.0966);
MVP		0.98
MPC		2.5
ClinPred		1.0	D
GERP RS		5.4
Varity_R		0.77
gMVP		0.97

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: rs121908215; hg19: chr19-13470521;