KCNA1 p.Cys228* – ACMG Classification: Pathogenic (10 pts)

Variant summary

Our verdict is . The variant received 10 ACMG points: 10P and 0B. PVS1PM2

The NM_000217.3(KCNA1):c.684T>A(p.Cys228*) variant causes a stop gained 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. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. C228C) has been classified as Benign.

Frequency

Genomes: not found (cov: 31)

Consequence

KCNA1
NM_000217.3 stop_gained

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 1.74

Publications

22 publications found

Variant links:

Genes affected

KCNA1 (HGNC:6218): (potassium voltage-gated channel subfamily A member 1) This gene encodes a voltage-gated delayed potassium channel that is phylogenetically related to the Drosophila Shaker channel. The encoded protein has six putative transmembrane segments (S1-S6), and the loop between S5 and S6 forms the pore and contains the conserved selectivity filter motif (GYGD). The functional channel is a homotetramer. The N-terminus of the channel is associated with beta subunits that can modify the inactivation properties of the channel as well as affect expression levels. The C-terminus of the channel is complexed to a PDZ domain protein that is responsible for channel targeting. Mutations in this gene have been associated with myokymia with periodic ataxia (AEMK). [provided by RefSeq, Jul 2008]

KCNA1 Gene-Disease associations (from GenCC):

episodic ataxia type 1
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet, Genomics England PanelApp
epilepsy
Inheritance: AD Classification: STRONG Submitted by: PanelApp Australia
episodic kinesigenic dyskinesia 1
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
genetic developmental and epileptic encephalopathy
Inheritance: AD, AR Classification: SUPPORTIVE, LIMITED Submitted by: G2P, Orphanet
isolated autosomal dominant hypomagnesemia, Glaudemans type
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

KCNA1 links:

ENSG00000256654 (HGNC:):

ENSG00000256654 links:

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new If you want to explore the variant's impact on the transcript NM_000217.3, check out the Mutation Effect Viewer. This is especially useful for frameshift variants or if you want to visualize the effect of exon loss / intron retention.

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 10 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 42 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000217.3. 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
	KCNA1	NM_000217.3	MANE Select	c.684T>A	p.Cys228*	stop_gained	Exon 2 of 2	NP_000208.2	Q09470

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
KCNA1	ENST00000382545.5	TSL:4 MANE Select	c.684T>A	p.Cys228*	stop_gained	Exon 2 of 2	ENSP00000371985.3	Q09470
KCNA1	ENST00000639306.1	TSL:5	n.522T>A		non_coding_transcript_exon	Exon 1 of 2	ENSP00000492506.1	A0A1W2PRI2
ENSG00000256654	ENST00000541095.1	TSL:3	n.105+1590T>A		intron	N/A

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

Cov.:

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

59723

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.62

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

Eigen

Uncertain

0.28

Eigen_PC

Benign

0.083

FATHMM_MKL

Uncertain

0.87

PhyloP100

1.7

PromoterAI

0.010

Neutral

(source)

Mutation Taster

=9/191

disease causing

(source)

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over