NM_004974.4:c.894G>T

Variant names:

• chr1-110603889-C-A
• rs876657390
• NM_004974.4:c.894G>T

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Moderate PP5_Moderate

The NM_004974.4(KCNA2):​c.894G>T​(p.Leu298Phe) variant causes a missense change involving the alteration of a non-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 Pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNA2 NM_004974.4 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 2.55
• Publications: 20 publications found

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]

KCNA2 Gene-Disease associations (from GenCC):

• developmental and epileptic encephalopathy, 32

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• genetic developmental and epileptic encephalopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• undetermined early-onset epileptic encephalopathy

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: ClinGen, Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PM1: In a hotspot region, there are 10 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_004974.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.913
• PP5: Variant 1-110603889-C-A is Pathogenic according to our data. Variant chr1-110603889-C-A is described in ClinVar as Pathogenic. ClinVar VariationId is 190327.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004974.4. 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
	KCNA2	NM_004974.4	MANE Select	c.894G>T	p.Leu298Phe	missense	Exon 3 of 3	NP_004965.1
	KCNA2	NM_001204269.2		c.894G>T	p.Leu298Phe	missense splice_region	Exon 3 of 5	NP_001191198.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNA2	ENST00000316361.10	TSL:2 MANE Select	c.894G>T	p.Leu298Phe	missense	Exon 3 of 3	ENSP00000314520.4
	KCNA2	ENST00000369770.7	TSL:1	c.894G>T	p.Leu298Phe	missense splice_region	Exon 3 of 5	ENSP00000358785.3
	KCNA2	ENST00000485317.6	TSL:5	c.894G>T	p.Leu298Phe	missense	Exon 3 of 3	ENSP00000433109.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
1	-	-	Developmental and epileptic encephalopathy, 32 (1)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	D
Eigen	Pathogenic	0.80
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Pathogenic	0.59	D
MetaRNN	Pathogenic	0.88	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Benign	2.0	M
PhyloP100		2.6
PrimateAI	Pathogenic	0.85	D
PROVEAN	Uncertain	-3.8	D
REVEL	Pathogenic	0.77
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.019	D
Polyphen		1.0	D
Vest4		0.76
MutPred		0.72		Loss of stability (P = 0.0945)
MVP		0.92
MPC		2.5
ClinPred		0.99	D
GERP RS		5.9
Varity_R		0.88
gMVP		0.96
Mutation Taster		=1/99	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs876657390; hg19: chr1-111146511;