rs121908222

Positions:

• chr19-13371735-C-T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PP2 PP3_Strong PP5_Moderate

The NM_001127222.2(CACNA1A):​c.584G>A​(p.Arg195Lys) 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:1 O:1
• Conservation: PhyloP100: 7.73

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 11 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, 11 uncertain in NM_001127222.2
• 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.942
• PP5: Variant 19-13371735-C-T is Pathogenic according to our data. Variant chr19-13371735-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 68439.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr19-13371735-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CACNA1A	NM_001127222.2	c.584G>A	p.Arg195Lys	missense_variant	4/47	ENST00000360228.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CACNA1A	ENST00000360228.11	c.584G>A	p.Arg195Lys	missense_variant	4/47	1	NM_001127222.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 19, 2022

ClinVar contains an entry for this variant (Variation ID: 68439). 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. This missense change has been observed in individual(s) with familial hemiplegic migraine (PMID: 11439943). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with lysine, which is basic and polar, at codon 195 of the CACNA1A protein (p.Arg195Lys). -

Migraine, familial hemiplegic, 1 Other:1

not provided, no classification provided

literature only

UniProtKB/Swiss-Prot

-

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.55
CADD	Pathogenic	29
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.95	.;D;T;.;.;.;.;.;.;T;.;.;.;T;.
Eigen	Pathogenic	0.86
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	1.0	D;D;D;D;D;D;D;D;.;D;D;D;D;D;D
M_CAP	Pathogenic	0.76	D
MetaRNN	Pathogenic	0.94	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;.;.;H;.;.;H;.;.;.;.;H;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Uncertain	-2.4	.;N;.;.;.;.;.;.;.;.;.;.;.;.;.
REVEL	Pathogenic	0.95
Sift	Uncertain	0.0010	.;D;.;.;.;.;.;.;.;.;.;.;.;.;.
Sift4G	Uncertain	0.0030	D;D;.;.;.;.;.;.;.;.;.;D;.;.;.
Polyphen		0.99	.;D;.;.;.;.;.;.;.;.;.;.;.;.;.
Vest4		0.81
MutPred		0.79		Loss of methylation at R195 (P = 0.0339);Loss of methylation at R195 (P = 0.0339);Loss of methylation at R195 (P = 0.0339);Loss of methylation at R195 (P = 0.0339);Loss of methylation at R195 (P = 0.0339);.;Loss of methylation at R195 (P = 0.0339);Loss of methylation at R195 (P = 0.0339);Loss of methylation at R195 (P = 0.0339);Loss of methylation at R195 (P = 0.0339);Loss of methylation at R195 (P = 0.0339);Loss of methylation at R195 (P = 0.0339);Loss of methylation at R195 (P = 0.0339);Loss of methylation at R195 (P = 0.0339);Loss of methylation at R195 (P = 0.0339);
MVP		0.99
MPC		1.8
ClinPred		0.99	D
GERP RS		4.9
Varity_R		0.83
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs121908222; hg19: chr19-13482549;