NM_004974.4:c.1304G>A

Variant names:

• chr1-110603479-C-T
• rs1553181236
• NM_004974.4:c.1304G>A

Variant summary

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

The NM_004974.4(KCNA2):​c.1304G>A​(p.Cys435Tyr) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,878 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C435S) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: KCNA2 NM_004974.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 4.88
• Publications: 0 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: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNA2	NM_004974.4	MANE Select	c.1304G>A	p.Cys435Tyr	missense	Exon 3 of 3	NP_004965.1	P16389-1
	KCNA2	NM_001204269.2		c.894+410G>A		intron	N/A	NP_001191198.1	P16389-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNA2	ENST00000316361.10	TSL:2 MANE Select	c.1304G>A	p.Cys435Tyr	missense	Exon 3 of 3	ENSP00000314520.4	P16389-1
	KCNA2	ENST00000369770.7	TSL:1	c.894+410G>A		intron	N/A	ENSP00000358785.3	P16389-2
	KCNA2	ENST00000485317.6	TSL:5	c.1304G>A	p.Cys435Tyr	missense	Exon 3 of 3	ENSP00000433109.1	P16389-1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461878 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 727236

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111998

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, multiple submitters, no conflicts

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	Benign	0.12
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.020
CADD	Uncertain	25
DANN	Benign	0.96
DEOGEN2	Pathogenic	0.85	D
Eigen	Uncertain	0.28
Eigen_PC	Uncertain	0.36
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Benign	0.85	T
M_CAP	Uncertain	0.15	D
MetaRNN	Uncertain	0.72	D
MetaSVM	Pathogenic	0.84	D
MutationAssessor	Uncertain	2.4	M
PhyloP100		4.9
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-6.1	D
REVEL	Uncertain	0.54
Sift	Benign	0.095	T
Sift4G	Uncertain	0.012	D
Polyphen		0.16	B
Vest4		0.43
MutPred		0.42		Loss of sheet (P = 0.0104)
MVP		0.61
MPC		2.0
ClinPred		0.78	D
GERP RS		4.9
Varity_R		0.45
gMVP		0.66
Mutation Taster		=73/27	polymorphism

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: rs1553181236; hg19: chr1-111146101;