rs992828062

chr19-13286592-T-Achr19-13286592-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_001127222.2(CACNA1A):c.3464A>T(p.Asn1155Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000216 in 1,390,118 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. N1155S) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 29)
  • Exomes 𝑓: 0.0000022 (0 hom.)
• Consequence: CACNA1A NM_001127222.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.843

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 Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, CACNA1A
• BP4: Computational evidence support a benign effect (MetaRNN=0.21824703).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CACNA1A	NM_001127222.2	c.3464A>T	p.Asn1155Ile	missense_variant	20/47	ENST00000360228.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CACNA1A	ENST00000360228.11	c.3464A>T	p.Asn1155Ile	missense_variant	20/47	1	NM_001127222.2

Frequencies

GnomAD3 genomes Cov.: 29

GnomAD3 exomes AF: 0.00000533 AC: 1 AN: 187546 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 99784

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000640

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000216 AC: 3 AN: 1390118 Hom.: 0 Cov.: 35 AF XY: 0.00000146 AC XY: 1 AN XY: 685772

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000513

Gnomad4 SAS exome AF: 0.0000136

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 29

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Mar 05, 2020

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with CACNA1A-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces asparagine with isoleucine at codon 1156 of the CACNA1A protein (p.Asn1156Ile). The asparagine residue is moderately conserved and there is a large physicochemical difference between asparagine and isoleucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Benign	-0.23	T
BayesDel_noAF	Benign	-0.39
Cadd	Benign	20
Dann	Benign	0.97
Eigen	Benign	-0.28
Eigen_PC	Benign	-0.17
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.89	D;D;D;D;D;D;D;D;.;D;D;D;D;D;D
M_CAP	Benign	0.057	D
MetaRNN	Benign	0.22	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-1.0	T
MutationTaster	Benign	0.90	N;N;N
PrimateAI	Uncertain	0.50	T
Sift4G	Benign	0.14	T;T;.;.;.;.;.;.;.;.;.;.;.;.;.
Vest4		0.57
MutPred		0.22		.;.;Loss of solvent accessibility (P = 0.0468);Loss of solvent accessibility (P = 0.0468);Loss of solvent accessibility (P = 0.0468);.;Loss of solvent accessibility (P = 0.0468);.;.;Loss of solvent accessibility (P = 0.0468);Loss of solvent accessibility (P = 0.0468);.;Loss of solvent accessibility (P = 0.0468);.;Loss of solvent accessibility (P = 0.0468);
MVP		0.54
MPC		0.091
ClinPred		0.52	D
GERP RS		2.1
Varity_R		0.26
gMVP		0.56

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: rs992828062; hg19: chr19-13397406;