rs1296710118

Positions:

• chr1-110603527-C-A
• chr1-110603527-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 5P and 2B. PM2 PP2 PP3_Moderate BP6_Moderate

The NM_004974.4(KCNA2):​c.1256G>T​(p.Arg419Leu) 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. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely benign (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R419Q) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNA2 NM_004974.4 missense
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 7.90

Genes affected

KCNA2 (HGNC:6220): (potassium voltage-gated channel subfamily A member 2) Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has been shown to have human homolog(s). This gene encodes a member of the potassium channel, voltage-gated, shaker-related subfamily. This member contains six membrane-spanning domains with a shaker-type repeat in the fourth segment. It belongs to the delayed rectifier class, members of which allow nerve cells to efficiently repolarize following an action potential. The coding region of this gene is intronless, and the gene is clustered with genes KCNA3 and KCNA10 on chromosome 1. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), KCNA2. . Gene score misZ: 3.831 (greater than the threshold 3.09). Trascript score misZ: 5.1665 (greater than threshold 3.09). The gene has 37 curated pathogenic missense variants (we use a threshold of 10). The gene has 14 curated benign missense variants. GenCC has associacion of the gene with undetermined early-onset epileptic encephalopathy, developmental and epileptic encephalopathy, developmental and epileptic encephalopathy, 32.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.884
• BP6: Variant 1-110603527-C-A is Benign according to our data. Variant chr1-110603527-C-A is described in ClinVar as [Likely_benign]. Clinvar id is 2147820.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNA2	NM_004974.4	c.1256G>T	p.Arg419Leu	missense_variant	3/3	ENST00000316361.10	NP_004965.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNA2	ENST00000316361.10	c.1256G>T	p.Arg419Leu	missense_variant	3/3	2	NM_004974.4	ENSP00000314520.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Developmental and epileptic encephalopathy, 32 Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 03, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.92
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.37
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.92	D;.;.;D;D;D;D;.
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	.;D;D;.;.;.;D;D
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.88	D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.5	M;.;.;M;M;M;M;.
PrimateAI	Pathogenic	0.92	D
PROVEAN	Pathogenic	-6.1	.;.;.;.;D;.;D;.
REVEL	Pathogenic	0.87
Sift	Pathogenic	0.0	.;.;.;.;D;.;D;.
Sift4G	Uncertain	0.052	T;.;.;.;T;.;T;.
Polyphen		1.0	D;.;.;D;D;D;D;.
Vest4		0.74
MutPred		0.44		Loss of disorder (P = 0.0519);.;.;Loss of disorder (P = 0.0519);Loss of disorder (P = 0.0519);Loss of disorder (P = 0.0519);Loss of disorder (P = 0.0519);.;
MVP		0.93
MPC		2.6
ClinPred		1.0	D
GERP RS		5.4
Varity_R		0.89
gMVP		0.88

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: rs1296710118; hg19: chr1-111146149;