NM_001127222.2:c.1171G>A

Variant names:

• chr19-13334405-C-T
• rs749309558
• NM_001127222.2:c.1171G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_001127222.2(CACNA1A):​c.1171G>A​(p.Gly391Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000138 in 1,445,904 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. G391G) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CACNA1A NM_001127222.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 7.75
• Publications: 1 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: Likely_pathogenic. The variant received 6 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 10 uncertain in NM_001127222.2
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.87

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.1171G>A	p.Gly391Arg	missense	Exon 8 of 47	NP_001120694.1
	CACNA1A	NM_001127221.2	MANE Plus Clinical	c.1171G>A	p.Gly391Arg	missense	Exon 8 of 47	NP_001120693.1
	CACNA1A	NM_023035.3		c.1171G>A	p.Gly391Arg	missense	Exon 8 of 48	NP_075461.2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CACNA1A	ENST00000360228.11	TSL:1 MANE Select	c.1171G>A	p.Gly391Arg	missense	Exon 8 of 47	ENSP00000353362.5
	CACNA1A	ENST00000638009.2	TSL:1 MANE Plus Clinical	c.1171G>A	p.Gly391Arg	missense	Exon 8 of 47	ENSP00000489913.1
	CACNA1A	ENST00000638029.1	TSL:5	c.1171G>A	p.Gly391Arg	missense	Exon 8 of 48	ENSP00000489829.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000802 AC: 2 AN: 249270 AF XY: 0.00000740

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000579

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000138 AC: 2 AN: 1445904 Hom.: 0 Cov.: 31 AF XY: 0.00000139 AC XY: 1 AN XY: 720270

⚠️ 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: 33190

American (AMR) AF: 0.0000447 AC: 2 AN: 44700

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26052

East Asian (EAS) AF: 0.00 AC: 0 AN: 39614

South Asian (SAS) AF: 0.00 AC: 0 AN: 85942

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53398

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5742

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1097412

Other (OTH) AF: 0.00 AC: 0 AN: 59854

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0296732), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ExAC AF: 0.00000827 AC: 1

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	1	-	Episodic ataxia type 2;C4310716:Developmental and epileptic encephalopathy, 42 (1)
-	1	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.21	D
BayesDel_noAF	Pathogenic	0.24
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.84	D
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Uncertain	0.23	D
MetaRNN	Pathogenic	0.87	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.4	M
PhyloP100		7.8
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-6.4	D
REVEL	Pathogenic	0.80
Sift	Uncertain	0.021	D
Sift4G	Uncertain	0.019	D
Polyphen		1.0	D
Vest4		0.82
MutPred		0.49		Gain of MoRF binding (P = 0.0102)
MVP		0.93
MPC		2.5
ClinPred		0.99	D
GERP RS		5.1
Varity_R		0.54
gMVP		0.99
Mutation Taster		=14/86	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.12		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: rs749309558; hg19: chr19-13445219; COSMIC: COSV64210282;