rs1064794808

chr19-13262768-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP2 PP3_Moderate PP5

The NM_001127222.2(CACNA1A):c.4055C>T(p.Pro1352Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CACNA1A NM_001127222.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3 U:1
• Conservation: PhyloP100: 9.88

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 Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a hotspot region, there are 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 2 uncertain in NM_001127222.2
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, CACNA1A
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.93
• PP5: Variant 19-13262768-G-A is Pathogenic according to our data. Variant chr19-13262768-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 420945.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=3, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CACNA1A	NM_001127222.2	c.4055C>T	p.Pro1352Leu	missense_variant	25/47	ENST00000360228.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CACNA1A	ENST00000360228.11	c.4055C>T	p.Pro1352Leu	missense_variant	25/47	1	NM_001127222.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:3 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Spinocerebellar ataxia type 6;C1720416:Episodic ataxia type 2;C1832884:Migraine, familial hemiplegic, 1;C4479236:Developmental and epileptic encephalopathy, 52 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Wendy Chung Laboratory, Columbia University Medical Center

Mar 20, 2022

- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Mar 22, 2017

The P1353L variant in the CACN1A gene has been reported previously as a presumed de novo finding in a child with global developmental delay and hypotonia (Weyhrauch et al., 2015; Lazaridis et al., 2016). The P1353L variant is not observed in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). The P1353L variant is a semi-conservative amino acid substitution, which may impact secondary protein structure as these residues differ in some properties. This substitution occurs at a position that is conserved across species. In vitro analysis of P1353L demonstrates that this variant results in nearly complete loss of calcium channel function (Weyhrauch et al., 2015). Furthermore, missense variants in nearby residues (R1349Q, V1350L) have been reported in the Human Gene Mutation Database in association with CACNA1A-related disorders (Stenson et al., 2014), supporting the functional importance of this region of the protein. Therefore, we interpret P1353L as a pathogenic variant. -

Developmental and epileptic encephalopathy, 42 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

-

- -

Episodic ataxia type 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Sep 01, 2017

Likely pathogenicity based on finding it once in our laboratory de novo in a 3-year-old male with global delays, axial hypotonia, limb hypertonia, ataxia, spasticity, myoclonus, pes planus, vision loss, coxa valga, kyphosis. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.32
Cadd	Pathogenic	29
Dann	Uncertain	1.0
Eigen	Uncertain	0.45
Eigen_PC	Uncertain	0.46
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.99	D;D;D;D;D;D;D;D;.;D;D;D;D;D;D
M_CAP	Pathogenic	0.82	D
MetaRNN	Pathogenic	0.93	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.94	D
Sift4G	Pathogenic	0.0	D;D;.;.;.;.;.;.;.;.;.;.;.;.;.
Vest4		0.93
MutPred		0.64		.;.;Gain of ubiquitination at K1355 (P = 0.0726);Gain of ubiquitination at K1355 (P = 0.0726);Gain of ubiquitination at K1355 (P = 0.0726);.;Gain of ubiquitination at K1355 (P = 0.0726);.;.;Gain of ubiquitination at K1355 (P = 0.0726);Gain of ubiquitination at K1355 (P = 0.0726);.;Gain of ubiquitination at K1355 (P = 0.0726);.;Gain of ubiquitination at K1355 (P = 0.0726);
MVP		0.97
MPC		2.5
ClinPred		1.0	D
GERP RS		4.4
Varity_R		0.89
gMVP		1.0

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: rs1064794808; hg19: chr19-13373582;