NM_006030.4:c.2777C>T

Variant names:

• chr3-50366096-G-A
• rs1553725746
• NM_006030.4:c.2777C>T

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_006030.4(CACNA2D2):​c.2777C>T​(p.Thr926Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,182 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: CACNA2D2 NM_006030.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.86
• Publications: 0 publications found

Genes affected

CACNA2D2 (HGNC:1400): (calcium voltage-gated channel auxiliary subunit alpha2delta 2) Calcium channels mediate the entry of calcium ions into the cell upon membrane polarization. This gene encodes the alpha-2/delta subunit of the voltage-dependent calcium channel complex. The complex consists of the main channel-forming subunit alpha-1, and auxiliary subunits alpha-2/delta, beta, and gamma. The auxiliary subunits function in the assembly and membrane localization of the complex, and modulate calcium currents and channel activation/inactivation kinetics. The subunit encoded by this gene undergoes post-translational cleavage to yield the extracellular alpha2 peptide and a membrane-anchored delta polypeptide. This subunit is a receptor for the antiepileptic drug, gabapentin. Mutations in this gene are associated with early infantile epileptic encephalopathy. Single nucleotide polymorphisms in this gene are correlated with increased sensitivity to opioid drugs. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Mar 2014]

CACNA2D2 Gene-Disease associations (from GenCC):

• cerebellar atrophy with seizures and variable developmental delay

  Inheritance: AR Classification: STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• complex neurodevelopmental disorder

  Inheritance: AR Classification: MODERATE Submitted by: ClinGen

ENSG00000272104 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.21118706).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_006030.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CACNA2D2	NM_006030.4	MANE Select	c.2777C>T	p.Thr926Ile	missense	Exon 32 of 38	NP_006021.2
	CACNA2D2	NM_001174051.3		c.2798C>T	p.Thr933Ile	missense	Exon 33 of 39	NP_001167522.1
	CACNA2D2	NM_001005505.3		c.2777C>T	p.Thr926Ile	missense	Exon 32 of 38	NP_001005505.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CACNA2D2	ENST00000424201.7	TSL:1 MANE Select	c.2777C>T	p.Thr926Ile	missense	Exon 32 of 38	ENSP00000390329.2
	CACNA2D2	ENST00000423994.6	TSL:5	c.2801C>T	p.Thr934Ile	missense	Exon 33 of 39	ENSP00000407393.2
	CACNA2D2	ENST00000479441.1	TSL:1	c.2798C>T	p.Thr933Ile	missense	Exon 33 of 39	ENSP00000418081.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152182 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 36

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152182 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74350

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

African (AFR) AF: 0.0000241 AC: 1 AN: 41440

American (AMR) AF: 0.00 AC: 0 AN: 15282

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10622

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68022

Other (OTH) AF: 0.00 AC: 0 AN: 2088

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Developmental and epileptic encephalopathy Uncertain:1

Aug 18, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a CACNA2D2-related disease. This sequence change replaces threonine with isoleucine at codon 926 of the CACNA2D2 protein (p.Thr926Ile). The threonine residue is moderately conserved and there is a moderate physicochemical difference between threonine and isoleucine.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Benign	-0.014	T
BayesDel_noAF	Benign	-0.26
CADD	Benign	20
DANN	Uncertain	1.0
DEOGEN2	Benign	0.015	T
Eigen	Benign	-0.19
Eigen_PC	Benign	-0.080
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Uncertain	0.90	D
M_CAP	Benign	0.059	D
MetaRNN	Benign	0.21	T
MetaSVM	Benign	-0.79	T
MutationAssessor	Benign	1.6	L
PhyloP100		1.9
PrimateAI	Uncertain	0.55	T
PROVEAN	Benign	-2.1	N
REVEL	Benign	0.18
Sift	Benign	0.053	T
Sift4G	Uncertain	0.024	D
Polyphen		0.70	P
Vest4		0.30
MutPred		0.35		Loss of disorder (P = 0.0461)
MVP		0.20
MPC		0.70
ClinPred		0.42	T
GERP RS		3.3
Varity_R		0.080
gMVP		0.36
Mutation Taster		=79/21	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs1553725746; hg19: chr3-50403527;