19-13245235-C-T

Variant names:

• chr19-13245235-C-T
• rs1555740805
• NM_001127222.2:c.4897G>A

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PM2 PP3_Strong PP5_Very_Strong

The NM_001127222.2(CACNA1A):​c.4897G>A​(p.Asp1633Asn) 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D1633E) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: CACNA1A NM_001127222.2 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6 O:1
• Conservation: PhyloP100: 7.87
• Publications: 1 publications found

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]

CACNA1A Gene-Disease associations (from GenCC):

• episodic ataxia type 2

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• undetermined early-onset epileptic encephalopathy

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, Illumina
• developmental and epileptic encephalopathy, 42

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• migraine, familial hemiplegic, 1

  Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• spinocerebellar ataxia type 6

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Orphanet
• benign paroxysmal torticollis of infancy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial or sporadic hemiplegic migraine

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Lennox-Gastaut syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 14 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984
• PP5: Variant 19-13245235-C-T is Pathogenic according to our data. Variant chr19-13245235-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 449943.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001127222.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CACNA1A	NM_001127222.2	MANE Select	c.4897G>A	p.Asp1633Asn	missense	Exon 31 of 47	NP_001120694.1
	CACNA1A	NM_001127221.2	MANE Plus Clinical	c.4900G>A	p.Asp1634Asn	missense	Exon 31 of 47	NP_001120693.1
	CACNA1A	NM_023035.3		c.4909G>A	p.Asp1637Asn	missense	Exon 31 of 48	NP_075461.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CACNA1A	ENST00000360228.11	TSL:1 MANE Select	c.4897G>A	p.Asp1633Asn	missense	Exon 31 of 47	ENSP00000353362.5
	CACNA1A	ENST00000638009.2	TSL:1 MANE Plus Clinical	c.4900G>A	p.Asp1634Asn	missense	Exon 31 of 47	ENSP00000489913.1
	CACNA1A	ENST00000638029.1	TSL:5	c.4909G>A	p.Asp1637Asn	missense	Exon 31 of 48	ENSP00000489829.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Feb 24, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 31785789, 29165669, 19344873, 33798445, 34445196)

Jul 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

CACNA1A: PS2, PM2, PS4:Moderate, PP2, PP3

Episodic ataxia type 2 Pathogenic:1

Jan 04, 2021

Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

Inborn genetic diseases Pathogenic:1

Jun 10, 2024

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.4900G>A (p.D1634N) alteration is located in coding exon 31 of the CACNA1A gene. This alteration results from a G to A substitution at nucleotide position 4900, causing the aspartic acid (D) at amino acid position 1634 to be replaced by an asparagine (N). ; however, it is unlikely to be causative of CACN1A-related spinocerebellar ataxia. This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This variant has been determined to be the result of a de novo mutation or reported as heterozygous in multiple individuals with features consistent with episodic ataxia, type 2 and CACNA1A-related neurologic disorders (Galatolo, 2021; Courage, 2021; Lipman, 2022; DECIPHER). This amino acid position is highly conserved in available vertebrate species. This missense alteration is located in a region that has a low rate of benign missense variation (Lek, 2016; Firth, 2009). The in silico prediction for this alteration is inconclusive. Based on the available evidence, this alteration is classified as pathogenic.

Spinocerebellar ataxia type 6;C1720416:Episodic ataxia type 2;C1832884:Migraine, familial hemiplegic, 1;C4479236:Developmental and epileptic encephalopathy, 52 Pathogenic:1

Mar 20, 2022

Wendy Chung Laboratory, Boston Children's Hospital

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

CACNA1A-related disorder Pathogenic:1

Jan 24, 2020

Illumina Laboratory Services, Illumina

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The CACNA1A c.4900G>A (p.Asp1634Asn) variant is a missense variant. It is reported as a de novo variant, though without confirmed parentage, in one individual in the DECIPHER database (Firth et al. 2009, patient 259278). The reported phenotype of this individual is consistent with CACNA1A-related disorders and includes global developmental delay, intellectual disability, sleep disturbance, unsteady gait, falls, behavioral abnormalities, brachycephaly, strabismus, and bilateral single transverse palmar creases. The p.Asp1634Asn variant has also been identified by clinical laboratories in individuals with neurodevelopmental phenotypes consistent with CACNA1A-related disorders and submitted to the ClinVar database (Landrum et al. 2018); however these cases are not reported in the published literature and clinical details are limited. This variant is not found in the Genome Aggregation Database in a region of good sequencing coverage, so the variant is presumed to be rare. The p.Asp1634Asn variant occurs at a conserved residue in the S3 transmembrane segment of domain IV of the voltage-dependent P/Q-type calcium channel subunit alpha-1A protein, though the function of this region is unknown. In silico predictions suggest a damaging consequence, however this has not been evaluated experimentally. Based on the collective evidence and the application of ACMG criteria, the p.Asp1634Asn variant is classified as likely pathogenic for CACNA1A-related disorders.

Spinocerebellar ataxia type 6;C1720416:Episodic ataxia type 2;C1832884:Migraine, familial hemiplegic, 1 Other:1

GenomeConnect, ClinGen

Significance: not provided

Review Status: no classification provided

Collection Method: phenotyping only

Variant classified as Likely pathogenic and reported on 05-05-2017 by GeneDx. GenomeConnect assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. GenomeConnect staff make no attempt to reinterpret the clinical significance of the variant.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.13
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Benign	0.36	T
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.86	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	0.99	D
MutationAssessor	Pathogenic	4.5	H
PhyloP100		7.9
PrimateAI	Pathogenic	0.90	D
PROVEAN	Pathogenic	-4.9	D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0040	D
Vest4		0.96
MutPred		0.92		Gain of MoRF binding (P = 0.1141)
MVP		0.98
MPC		2.4
ClinPred		1.0	D
GERP RS		4.7
Varity_R		0.86
gMVP		1.0
Mutation Taster		=2/98	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs1555740805; hg19: chr19-13356049;