NM_001127222.2:c.6608A>G

Variant names:

• chr19-13208928-T-C
• rs1057521770
• NM_001127222.2:c.6608A>G

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4 BS2

The NM_001127222.2(CACNA1A):​c.6608A>G​(p.Lys2203Arg) variant causes a missense change. The variant allele was found at a frequency of 0.0000101 in 1,385,208 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. K2203N) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000010 (0 hom.)
• Consequence: CACNA1A NM_001127222.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 5.68
• Publications: 0 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

ENSG00000300728 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -5 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.2659246).
• BS2: High AC in GnomAdExome4 at 14 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CACNA1A	NM_001127222.2	c.6608A>G	p.Lys2203Arg	missense_variant	Exon 46 of 47	ENST00000360228.11	NP_001120694.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CACNA1A	ENST00000360228.11	c.6608A>G	p.Lys2203Arg	missense_variant	Exon 46 of 47	1	NM_001127222.2	ENSP00000353362.5
CACNA1A	ENST00000638029.1	c.6626A>G	p.Lys2209Arg	missense_variant	Exon 47 of 48	5		ENSP00000489829.1
CACNA1A	ENST00000573710.7	c.6614A>G	p.Lys2205Arg	missense_variant	Exon 46 of 47	5		ENSP00000460092.3
CACNA1A	ENST00000635727.1	c.6611A>G	p.Lys2204Arg	missense_variant	Exon 46 of 47	5		ENSP00000490001.1
CACNA1A	ENST00000637769.1	c.6611A>G	p.Lys2204Arg	missense_variant	Exon 46 of 47	1		ENSP00000489778.1
CACNA1A	ENST00000636012.1	c.6575A>G	p.Lys2192Arg	missense_variant	Exon 45 of 46	5		ENSP00000490223.1
CACNA1A	ENST00000637736.1	c.6470A>G	p.Lys2157Arg	missense_variant	Exon 45 of 46	5		ENSP00000489861.1
CACNA1A	ENST00000636389.1	c.6611A>G	p.Lys2204Arg	missense_variant	Exon 46 of 47	5		ENSP00000489992.1
CACNA1A	ENST00000637432.1	c.6626A>G	p.Lys2209Arg	missense_variant	Exon 47 of 48	5		ENSP00000490617.1
CACNA1A	ENST00000636549.1	c.6617A>G	p.Lys2206Arg	missense_variant	Exon 47 of 48	5		ENSP00000490578.1
CACNA1A	ENST00000637927.1	c.6614A>G	p.Lys2205Arg	missense_variant	Exon 46 of 47	5		ENSP00000489715.1
CACNA1A	ENST00000635895.1	c.6611A>G	p.Lys2204Arg	missense_variant	Exon 46 of 47	5		ENSP00000490323.1
CACNA1A	ENST00000638009.2	c.6611A>G	p.Lys2204Arg	missense_variant	Exon 46 of 47	1		ENSP00000489913.1
CACNA1A	ENST00000637276.1	c.6575A>G	p.Lys2192Arg	missense_variant	Exon 45 of 46	5		ENSP00000489777.1
CACNA1A	ENST00000636768.2	n.*874A>G		non_coding_transcript_exon_variant	Exon 44 of 45	5		ENSP00000490190.2
CACNA1A	ENST00000713789.1	n.*1787A>G		non_coding_transcript_exon_variant	Exon 46 of 47			ENSP00000519091.1
CACNA1A	ENST00000636768.2	n.*874A>G		3_prime_UTR_variant	Exon 44 of 45	5		ENSP00000490190.2
CACNA1A	ENST00000713789.1	n.*1787A>G		3_prime_UTR_variant	Exon 46 of 47			ENSP00000519091.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.0000142 AC: 2 AN: 141052 AF XY: 0.0000132

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000354

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000101 AC: 14 AN: 1385208 Hom.: 0 Cov.: 37 AF XY: 0.0000117 AC XY: 8 AN XY: 683672

African (AFR) AF: 0.00 AC: 0 AN: 31592

American (AMR) AF: 0.00 AC: 0 AN: 35704

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25176

East Asian (EAS) AF: 0.00 AC: 0 AN: 35734

South Asian (SAS) AF: 0.00 AC: 0 AN: 79232

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 35290

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5664

European-Non Finnish (NFE) AF: 0.0000130 AC: 14 AN: 1078896

Other (OTH) AF: 0.00 AC: 0 AN: 57920

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

Mar 13, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. This sequence change replaces lysine, which is basic and polar, with arginine, which is basic and polar, at codon 2204 of the CACNA1A protein (p.Lys2204Arg). This variant is present in population databases (no rsID available, gnomAD 0.004%). 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: 383881). 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. -

not provided Uncertain:1

Mar 12, 2024

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Spinocerebellar ataxia type 6;C1720416:Episodic ataxia type 2;C1832884:Migraine, familial hemiplegic, 1;C4310716:Developmental and epileptic encephalopathy, 42 Uncertain:1

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Uncertain	0.055	T
BayesDel_noAF	Uncertain	-0.050
CADD	Uncertain	23
DANN	Benign	0.97
DEOGEN2	Benign	0.019	.;.;T;.;.;.;.;.;T;.;.;T;.;.;.;T;.;.
Eigen	Benign	-0.18
Eigen_PC	Benign	-0.051
FATHMM_MKL	Uncertain	0.81	D
LIST_S2	Uncertain	0.87	D;D;D;D;D;D;D;D;D;D;.;D;D;D;D;D;D;D
M_CAP	Uncertain	0.26	D
MetaRNN	Benign	0.27	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	0.40	D
MutationAssessor	Uncertain	2.2	.;.;.;.;M;.;.;.;.;.;.;.;.;.;.;.;.;.
PhyloP100		5.7
PrimateAI	Uncertain	0.79	T
PROVEAN	Benign	-1.0	.;N;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
REVEL	Uncertain	0.35
Sift	Benign	0.19	.;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
Sift4G	Benign	0.28	T;T;.;.;.;T;.;.;.;.;.;.;.;.;.;.;.;.
Vest4		0.38
MutPred		0.30		.;.;Loss of methylation at K2204 (P = 0.0098);Loss of methylation at K2204 (P = 0.0098);Loss of methylation at K2204 (P = 0.0098);.;.;Loss of methylation at K2204 (P = 0.0098);.;.;.;.;Loss of methylation at K2204 (P = 0.0098);.;.;.;.;.;
MVP		0.92
MPC		0.22
ClinPred		0.40	T
GERP RS		3.7
Varity_R		0.096
gMVP		0.14
Mutation Taster		=80/20	polymorphism

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

Other links and lift over

dbSNP: rs1057521770; hg19: chr19-13319742;