rs121908220

chr19-13235685-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 NM_001127222.2(CACNA1A):c.4996C>T(p.Arg1666Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,652 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R1666Q) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CACNA1A NM_001127222.2 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3 O:1
• Conservation: PhyloP100: 2.30

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 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_001127222.2
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr19-13235684-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 638582.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant where missense usually causes diseases, CACNA1A
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.961
• PP5: Variant 19-13235685-G-A is Pathogenic according to our data. Variant chr19-13235685-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 68433.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr19-13235685-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CACNA1A	NM_001127222.2	c.4996C>T	p.Arg1666Trp	missense_variant	32/47	ENST00000360228.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CACNA1A	ENST00000360228.11	c.4996C>T	p.Arg1666Trp	missense_variant	32/47	1	NM_001127222.2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461652 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727100

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: 8.99e-7

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Migraine, familial hemiplegic, 1 Pathogenic:2 Other:1

Pathogenic, criteria provided, single submitter	clinical testing	Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen	Jun 13, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Center of Genomic medicine, Geneva, University Hospital of Geneva	Apr 25, 2016	Pathogenic variants in CACNA1A have been reported to cause familial hemiplegic migraine. Here we report a case of a female patient with hemiplegic migraine caused by a pathogenic variant in CACNA1A. -
not provided, no classification provided	literature only	UniProtKB/Swiss-Prot	-	- -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Athena Diagnostics

Aug 12, 2019

Not found in the total gnomAD dataset, and the data is high quality (0/278210 chr). Found in at least one symptomatic patient. Predicted to have a damaging effect on the protein. Statistically associated with disease, but in a single family (p < 0.05). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
Cadd	Pathogenic	33
Dann	Uncertain	1.0
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.72
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	0.99	D;D;D;D;D;D;D;D;D;D;.;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.89	D
MetaRNN	Pathogenic	0.96	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.93	D
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.91	D
Sift4G	Pathogenic	0.0	D;D;.;.;.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.
Vest4		0.96
MutPred		0.81		.;.;Loss of methylation at R1667 (P = 0.0329);Loss of methylation at R1667 (P = 0.0329);Loss of methylation at R1667 (P = 0.0329);.;.;Loss of methylation at R1667 (P = 0.0329);.;.;.;Loss of methylation at R1667 (P = 0.0329);Loss of methylation at R1667 (P = 0.0329);.;Loss of methylation at R1667 (P = 0.0329);.;.;.;.;.;
MVP		0.95
MPC		1.9
ClinPred		1.0	D
GERP RS		3.9
Varity_R		0.88
gMVP		0.99

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs121908220; hg19: chr19-13346499;