chr19-13209016-C-T

Variant names:

• chr19-13209016-C-T
• rs1555730686
• NM_001127222.2:c.6527-7G>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_001127222.2(CACNA1A):​c.6527-7G>A variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000722 in 1,384,716 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.2e-7 (0 hom.)
• Consequence: CACNA1A NM_001127222.2 splice_region, intron
• Scores: Splicing: ADA: 0.9997
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.200
• 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: Labcorp Genetics (formerly Invitae), Ambry Genetics, Genomics England PanelApp, Orphanet
• undetermined early-onset epileptic encephalopathy

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Illumina, Orphanet
• developmental and epileptic encephalopathy, 42

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• migraine, familial hemiplegic, 1

  Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• spinocerebellar ataxia type 6

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Ambry Genetics
• 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: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001127222.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CACNA1A	NM_001127222.2	MANE Select	c.6527-7G>A		splice_region intron	N/A	NP_001120694.1	O00555-8
	CACNA1A	NM_001127221.2	MANE Plus Clinical	c.6530-7G>A		splice_region intron	N/A	NP_001120693.1	O00555-3
	CACNA1A	NM_023035.3		c.6545-7G>A		splice_region intron	N/A	NP_075461.2	A0A087WW63

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CACNA1A	ENST00000360228.11	TSL:1 MANE Select	c.6527-7G>A		splice_region intron	N/A	ENSP00000353362.5	O00555-8
	CACNA1A	ENST00000638009.2	TSL:1 MANE Plus Clinical	c.6530-7G>A		splice_region intron	N/A	ENSP00000489913.1	O00555-3
	CACNA1A	ENST00000638029.1	TSL:5	c.6545-7G>A		splice_region intron	N/A	ENSP00000489829.1	A0A087WW63

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 7.22e-7 AC: 1 AN: 1384716 Hom.: 0 Cov.: 37 AF XY: 0.00 AC XY: 0 AN XY: 683348

⚠️ 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: 31592

American (AMR) AF: 0.00 AC: 0 AN: 35692

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25170

East Asian (EAS) AF: 0.00 AC: 0 AN: 35730

South Asian (SAS) AF: 0.00 AC: 0 AN: 79234

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 34812

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5690

European-Non Finnish (NFE) AF: 9.27e-7 AC: 1 AN: 1078868

Other (OTH) AF: 0.00 AC: 0 AN: 57928

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Episodic ataxia type 2;C4310716:Developmental and epileptic encephalopathy, 42 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.68
CADD	Benign	22
DANN	Benign	0.89
PhyloP100		0.20

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.98
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.99		Position offset: -2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1555730686; hg19: chr19-13319830;