chr19-13298819-GC-G

Variant names:

• chr19-13298819-GC-G
• rs587776694
• NM_001127222.2:c.2813delG

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_001127222.2(CACNA1A):​c.2813delG​(p.Gly938AlafsTer131) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000705 in 1,418,414 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 7.1e-7 (0 hom.)
• Consequence: CACNA1A NM_001127222.2 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 0.199
• 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

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 19-13298819-GC-G is Pathogenic according to our data. Variant chr19-13298819-GC-G is described in ClinVar as [Pathogenic]. Clinvar id is 2925639.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CACNA1A	NM_001127222.2	c.2813delG	p.Gly938AlafsTer131	frameshift_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.2813delG	p.Gly938AlafsTer131	frameshift_variant	Exon 19 of 47	1	NM_001127222.2	ENSP00000353362.5
CACNA1A	ENST00000638029.1	c.2825delG	p.Gly942AlafsTer131	frameshift_variant	Exon 19 of 48	5		ENSP00000489829.1
CACNA1A	ENST00000573710.7	c.2819delG	p.Gly940AlafsTer131	frameshift_variant	Exon 19 of 47	5		ENSP00000460092.3
CACNA1A	ENST00000635727.1	c.2816delG	p.Gly939AlafsTer131	frameshift_variant	Exon 19 of 47	5		ENSP00000490001.1
CACNA1A	ENST00000637769.1	c.2816delG	p.Gly939AlafsTer131	frameshift_variant	Exon 19 of 47	1		ENSP00000489778.1
CACNA1A	ENST00000636012.1	c.2816delG	p.Gly939AlafsTer131	frameshift_variant	Exon 19 of 46	5		ENSP00000490223.1
CACNA1A	ENST00000637736.1	c.2675delG	p.Gly892AlafsTer131	frameshift_variant	Exon 18 of 46	5		ENSP00000489861.1
CACNA1A	ENST00000636389.1	c.2816delG	p.Gly939AlafsTer131	frameshift_variant	Exon 19 of 47	5		ENSP00000489992.1
CACNA1A	ENST00000637432.1	c.2825delG	p.Gly942AlafsTer131	frameshift_variant	Exon 19 of 48	5		ENSP00000490617.1
CACNA1A	ENST00000636549.1	c.2816delG	p.Gly939AlafsTer131	frameshift_variant	Exon 19 of 48	5		ENSP00000490578.1
CACNA1A	ENST00000637927.1	c.2819delG	p.Gly940AlafsTer131	frameshift_variant	Exon 19 of 47	5		ENSP00000489715.1
CACNA1A	ENST00000635895.1	c.2816delG	p.Gly939AlafsTer131	frameshift_variant	Exon 19 of 47	5		ENSP00000490323.1
CACNA1A	ENST00000638009.2	c.2816delG	p.Gly939AlafsTer131	frameshift_variant	Exon 19 of 47	1		ENSP00000489913.1
CACNA1A	ENST00000637276.1	c.2816delG	p.Gly939AlafsTer131	frameshift_variant	Exon 19 of 46	5		ENSP00000489777.1
CACNA1A	ENST00000636768.2	n.2816delG		non_coding_transcript_exon_variant	Exon 19 of 45	5		ENSP00000490190.2
CACNA1A	ENST00000713789.1	n.2813delG		non_coding_transcript_exon_variant	Exon 19 of 47			ENSP00000519091.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 7.05e-7 AC: 1 AN: 1418414 Hom.: 0 Cov.: 32 AF XY: 0.00000142 AC XY: 1 AN XY: 704450

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 30850

American (AMR) AF: 0.00 AC: 0 AN: 41760

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25048

East Asian (EAS) AF: 0.00 AC: 0 AN: 37306

South Asian (SAS) AF: 0.00 AC: 0 AN: 82098

European-Finnish (FIN) AF: 0.0000272 AC: 1 AN: 36798

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4706

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1100980

Other (OTH) AF: 0.00 AC: 0 AN: 58868

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Dec 07, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. This premature translational stop signal has been observed in individual(s) with CACNA1A- related conditions (PMID: 19864665). This sequence change creates a premature translational stop signal (p.Gly939Alafs*131) in the CACNA1A gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in CACNA1A are known to be pathogenic (PMID: 10371528, 19486177, 25735478, 27250579). This variant is not present in population databases (gnomAD no frequency). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		0.20
Mutation Taster		=1/199	disease causing (fs/PTC)

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: rs587776694; hg19: chr19-13409633; COSMIC: COSV64198872;