rs121908243

Positions:

• chr19-13235649-G-A

Variant summary

Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The ENST00000360228.11(CACNA1A):​c.5032C>T​(p.Arg1678Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,613,742 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1678H) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CACNA1A ENST00000360228.11 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3 U:1 O:1
• Conservation: PhyloP100: 9.94

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 Pathogenic. Variant got 19 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in ENST00000360228.11
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr19-13235648-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 838346.Status of the report is criteria_provided_single_submitter, 1 stars.
• 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.979
• PP5: Variant 19-13235649-G-A is Pathogenic according to our data. Variant chr19-13235649-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 68434.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CACNA1A	NM_001127222.2	c.5032C>T	p.Arg1678Cys	missense_variant	32/47	ENST00000360228.11	NP_001120694.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CACNA1A	ENST00000360228.11	c.5032C>T	p.Arg1678Cys	missense_variant	32/47	1	NM_001127222.2	ENSP00000353362

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152222 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461520 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727072

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152222 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 74384

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3 Uncertain:1 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1 Uncertain:1

Uncertain significance, flagged submission	clinical testing	Revvity Omics, Revvity	Jul 23, 2019	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Jul 01, 2023	The frequency of this variant in the general population is consistent with pathogenicity (http://gnomad.broadinstitute.org). This variant has been identified in multiple unrelated individuals with episodic ataxia. This variant is also referred to as Arg1680Cys in published literature. Computational tools predict that this variant is damaging. -

Episodic ataxia type 2 Pathogenic:1 Other:1

not provided, no classification provided	literature only	UniProtKB/Swiss-Prot	-	- -
Pathogenic, no assertion criteria provided	research	Department of Rehabilitation Medicine, Incheon St. Mary’s Hospital, College of Medicine, The Catholic University of Korea	Feb 11, 2019	- -

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

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 10, 2023

For these reasons, this variant has been classified as Pathogenic. 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 expected to disrupt CACNA1A protein function. ClinVar contains an entry for this variant (Variation ID: 68434). This variant is also known as p.Arg1680Cys. This missense change has been observed in individuals with episodic ataxia type 2 (PMID: 20129625, 34085110; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 1679 of the CACNA1A protein (p.Arg1679Cys). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	34
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.50	.;.;D;.;.;.;.;.;D;.;.;D;.;.;.;D;.;.;.;.
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	D;D;D;D;D;D;D;D;D;D;.;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.83	D
MetaRNN	Pathogenic	0.98	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
MutationAssessor	Pathogenic	5.0	.;.;.;.;H;.;.;.;.;.;.;.;.;.;H;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.93	D
PROVEAN	Pathogenic	-7.7	.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
Sift4G	Pathogenic	0.0	D;D;.;.;.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.
Vest4		0.94
MutPred		0.84		.;.;Loss of MoRF binding (P = 0.0149);Loss of MoRF binding (P = 0.0149);Loss of MoRF binding (P = 0.0149);.;.;Loss of MoRF binding (P = 0.0149);.;.;.;Loss of MoRF binding (P = 0.0149);Loss of MoRF binding (P = 0.0149);.;Loss of MoRF binding (P = 0.0149);.;.;.;.;.;
MVP		0.99
MPC		2.0
ClinPred		1.0	D
GERP RS		5.0
Varity_R		0.87
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: rs121908243; hg19: chr19-13346463;