rs751726770

Positions:

• chr19-13298941-C-G
• chr19-13298941-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_001127222.2(CACNA1A):​c.2692G>C​(p.Gly898Arg) variant causes a missense change. The variant allele was found at a frequency of 0.000000694 in 1,440,550 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: CACNA1A NM_001127222.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 4.75

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 2 ACMG points.

• 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.2653566).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CACNA1A	NM_001127222.2	c.2692G>C	p.Gly898Arg	missense_variant	19/47	ENST00000360228.11	NP_001120694.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CACNA1A	ENST00000360228.11	c.2692G>C	p.Gly898Arg	missense_variant	19/47	1	NM_001127222.2	ENSP00000353362

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.94e-7 AC: 1 AN: 1440550 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 716688

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000227

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Sep 23, 2024	Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis indicates that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -
Uncertain significance, criteria provided, single submitter	clinical testing	Athena Diagnostics	Nov 13, 2017	- -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 27, 2023

This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 899 of the CACNA1A protein (p.Gly899Arg). This variant is present in population databases (no rsID available, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with CACNA1A-related conditions. ClinVar contains an entry for this variant (Variation ID: 585558). 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 not expected to disrupt CACNA1A protein function with a negative predictive value of 95%. 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. -

Developmental and epileptic encephalopathy, 42 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

New York Genome Center

Feb 05, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Uncertain	0.094	D
BayesDel_noAF	Uncertain	-0.010
CADD	Uncertain	24
DANN	Benign	0.93
DEOGEN2	Benign	0.017	.;.;T;.;.;.;.;.;.;T;.;.;.;T;.
Eigen	Benign	-0.38
Eigen_PC	Benign	-0.51
FATHMM_MKL	Uncertain	0.82	D
LIST_S2	Uncertain	0.92	D;D;D;D;D;D;D;D;.;D;D;D;D;D;D
M_CAP	Pathogenic	0.92	D
MetaRNN	Benign	0.27	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	0.17	D
MutationAssessor	Benign	1.5	.;.;.;.;L;.;.;.;.;.;.;.;L;.;.
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Pathogenic	0.87	D
PROVEAN	Benign	-0.45	.;N;.;.;.;.;.;.;.;.;.;.;.;.;.
REVEL	Uncertain	0.36
Sift	Benign	0.20	.;T;.;.;.;.;.;.;.;.;.;.;.;.;.
Sift4G	Benign	0.44	T;T;.;.;.;.;.;.;.;.;.;.;.;.;.
Vest4		0.43
MutPred		0.19		.;.;Gain of solvent accessibility (P = 0.0097);Gain of solvent accessibility (P = 0.0097);Gain of solvent accessibility (P = 0.0097);.;Gain of solvent accessibility (P = 0.0097);.;.;Gain of solvent accessibility (P = 0.0097);Gain of solvent accessibility (P = 0.0097);.;Gain of solvent accessibility (P = 0.0097);.;Gain of solvent accessibility (P = 0.0097);
MVP		0.93
MPC		2.3
ClinPred		0.39	T
GERP RS		3.0
Varity_R		0.075
gMVP		0.55

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: rs751726770; hg19: chr19-13409755;