19-13298827-G-C

Variant names:

• chr19-13298827-G-C
• rs1318353774
• NM_001127222.2:c.2806C>G

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.2806C>G​(p.Gln936Glu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000281 in 1,423,492 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: 33)
  • Exomes 𝑓: 0.0000028 (0 hom.)
• Consequence: CACNA1A NM_001127222.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.53

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 in the CACNA1A gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 137 curated pathogenic missense variants (we use a threshold of 10). The gene has 132 curated benign missense variants. Gene score misZ: 5.7845 (above the threshold of 3.09). Trascript score misZ: 3.9354 (above the threshold of 3.09). GenCC associations: The gene is linked to 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=0.22449744).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CACNA1A	NM_001127222.2	c.2806C>G	p.Gln936Glu	missense_variant	Exon 19 of 47	ENST00000360228.11	NP_001120694.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CACNA1A	ENST00000360228.11	c.2806C>G	p.Gln936Glu	missense_variant	Exon 19 of 47	1	NM_001127222.2	ENSP00000353362.5
CACNA1A	ENST00000638029.1	c.2818C>G	p.Gln940Glu	missense_variant	Exon 19 of 48	5		ENSP00000489829.1
CACNA1A	ENST00000573710.7	c.2812C>G	p.Gln938Glu	missense_variant	Exon 19 of 47	5		ENSP00000460092.3
CACNA1A	ENST00000635727.1	c.2809C>G	p.Gln937Glu	missense_variant	Exon 19 of 47	5		ENSP00000490001.1
CACNA1A	ENST00000637769.1	c.2809C>G	p.Gln937Glu	missense_variant	Exon 19 of 47	1		ENSP00000489778.1
CACNA1A	ENST00000636012.1	c.2809C>G	p.Gln937Glu	missense_variant	Exon 19 of 46	5		ENSP00000490223.1
CACNA1A	ENST00000637736.1	c.2668C>G	p.Gln890Glu	missense_variant	Exon 18 of 46	5		ENSP00000489861.1
CACNA1A	ENST00000636389.1	c.2809C>G	p.Gln937Glu	missense_variant	Exon 19 of 47	5		ENSP00000489992.1
CACNA1A	ENST00000637432.1	c.2818C>G	p.Gln940Glu	missense_variant	Exon 19 of 48	5		ENSP00000490617.1
CACNA1A	ENST00000636549.1	c.2809C>G	p.Gln937Glu	missense_variant	Exon 19 of 48	5		ENSP00000490578.1
CACNA1A	ENST00000637927.1	c.2812C>G	p.Gln938Glu	missense_variant	Exon 19 of 47	5		ENSP00000489715.1
CACNA1A	ENST00000635895.1	c.2809C>G	p.Gln937Glu	missense_variant	Exon 19 of 47	5		ENSP00000490323.1
CACNA1A	ENST00000638009.2	c.2809C>G	p.Gln937Glu	missense_variant	Exon 19 of 47	1		ENSP00000489913.1
CACNA1A	ENST00000637276.1	c.2809C>G	p.Gln937Glu	missense_variant	Exon 19 of 46	5		ENSP00000489777.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000281 AC: 4 AN: 1423492 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 707194

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: 0.00000272

Gnomad4 OTH exome AF: 0.0000169

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000756

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

Jun 02, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is not present in population databases (ExAC no frequency). This sequence change replaces glutamine with glutamic acid at codon 937 of the CACNA1A protein (p.Gln937Glu). The glutamine residue is weakly conserved and there is a small physicochemical difference between glutamine and glutamic acid. This variant has not been reported in the literature in individuals with CACNA1A-related conditions. 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. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Uncertain	0.12	D
BayesDel_noAF	Uncertain	-0.060
CADD	Benign	19
DANN	Benign	0.40
DEOGEN2	Benign	0.0078	.;.;T;.;.;.;.;.;.;T;.;.;.;T;.
Eigen	Benign	-0.69
Eigen_PC	Benign	-0.63
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.86	D;D;D;D;D;D;D;D;.;D;D;D;D;D;D
M_CAP	Pathogenic	0.89	D
MetaRNN	Benign	0.22	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.30	T
MutationAssessor	Benign	0.81	.;.;.;.;L;.;.;.;.;.;.;.;L;.;.
PrimateAI	Pathogenic	0.85	D
PROVEAN	Benign	-0.52	.;N;.;.;.;.;.;.;.;.;.;.;.;.;.
REVEL	Uncertain	0.42
Sift	Benign	1.0	.;T;.;.;.;.;.;.;.;.;.;.;.;.;.
Sift4G	Benign	1.0	T;T;.;.;.;.;.;.;.;.;.;.;.;.;.
Vest4		0.16
MutPred		0.19		.;.;Loss of glycosylation at S940 (P = 0.172);Loss of glycosylation at S940 (P = 0.172);Loss of glycosylation at S940 (P = 0.172);.;Loss of glycosylation at S940 (P = 0.172);.;.;Loss of glycosylation at S940 (P = 0.172);Loss of glycosylation at S940 (P = 0.172);.;Loss of glycosylation at S940 (P = 0.172);.;Loss of glycosylation at S940 (P = 0.172);
MVP		0.95
MPC		1.3
ClinPred		0.096	T
GERP RS		3.8
Varity_R		0.074
gMVP		0.50

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: rs1318353774; hg19: chr19-13409641;