NM_000217.3:c.724G>A

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1PM2PM5PP2PP3

The NM_000217.3(KCNA1):c.724G>A(p.Ala242Thr) variant causes a missense change. The variant allele was found at a frequency of 0.00000658 in 151,894 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A242V) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 31)

Consequence

KCNA1
NM_000217.3 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 6.81

Publications

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

KCNA1 links:

ENSG00000256654 (HGNC:):

ENSG00000256654 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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

PM1

In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_000217.3

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr12-4912102-G-C is described in ClinVar as Pathogenic. ClinVar VariationId is 13489.Status of the report is criteria_provided_single_submitter, 1 stars.

PP2

Missense variant in the KCNA1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 33 curated pathogenic missense variants (we use a threshold of 10). The gene has 3 curated benign missense variants. Gene score misZ: 3.3255 (above the threshold of 3.09). Trascript score misZ: 3.8671 (above the threshold of 3.09). GenCC associations: The gene is linked to isolated autosomal dominant hypomagnesemia, Glaudemans type, episodic ataxia type 1, genetic developmental and epileptic encephalopathy, episodic kinesigenic dyskinesia 1.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.781

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNA1	NM_000217.3	MANE Select	c.724G>A	p.Ala242Thr	missense	Exon 2 of 2	NP_000208.2

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
KCNA1	ENST00000382545.5	TSL:4 MANE Select	c.724G>A	p.Ala242Thr	missense	Exon 2 of 2	ENSP00000371985.3
KCNA1	ENST00000639306.1	TSL:5	n.562G>A		non_coding_transcript_exon	Exon 1 of 2	ENSP00000492506.1
ENSG00000256654	ENST00000541095.1	TSL:3	n.105+1630G>A		intron	N/A

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

151894

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

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.:

GnomAD4 genome

AF:

0.00000658

AC:

AN:

151894

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74164

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41354

American (AMR)

AF:

0.0000655

AC:

AN:

15256

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5162

South Asian (SAS)

AF:

0.00

AC:

AN:

4790

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10560

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67996

Other (OTH)

AF:

0.00

AC:

AN:

2080

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.31

BayesDel_addAF

Pathogenic

0.24

BayesDel_noAF

Uncertain

0.11

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Pathogenic

0.92

Eigen

Benign

-0.075

Eigen_PC

Benign

0.058

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.86

M_CAP

Pathogenic

0.36

MetaRNN

Pathogenic

0.78

MetaSVM

Pathogenic

0.95

MutationAssessor

Benign

0.55

PhyloP100

6.8

PrimateAI

Pathogenic

0.83

PROVEAN

Uncertain

-3.2

REVEL

Pathogenic

0.75

Sift

Benign

0.056

Sift4G

Benign

0.20

Polyphen

0.28

Vest4

0.66

MutPred

0.70

Gain of catalytic residue at K246 (P = 0.0067)

MVP

0.96

MPC

1.7

ClinPred

0.98

GERP RS

4.1

PromoterAI

-0.013

Neutral

(source)

Varity_R

0.41

gMVP

0.83

Mutation Taster

=41/59

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

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