12-4911492-C-T

Variant names:

Variant summary

Our verdict is Benign. The variant received -15 ACMG points: 0P and 15B. BP4_ModerateBP6_Very_StrongBP7BS1

The NM_000217.3(KCNA1):c.114C>T(p.Arg38Arg) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000211 in 1,614,124 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Synonymous variant affecting the same amino acid position (i.e. R38R) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.00017 ( 0 hom., cov: 31)

Exomes 𝑓: 0.00021 ( 1 hom. )

Consequence

KCNA1
NM_000217.3 synonymous

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:5

Conservation

PhyloP100: -0.422

Publications

1 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: Benign. The variant received -15 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.38).

BP6

Variant 12-4911492-C-T is Benign according to our data. Variant chr12-4911492-C-T is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 447608.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=-0.422 with no splicing effect.

BS1

Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.000171 (26/152276) while in subpopulation NFE AF = 0.000353 (24/68022). AF 95% confidence interval is 0.000243. There are 0 homozygotes in GnomAd4. There are 13 alleles in the male GnomAd4 subpopulation. Median coverage is 31. This position passed quality control check.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNA1	NM_000217.3 link	c.114C>T	p.Arg38Arg	synonymous_variant	Exon 2 of 2	ENST00000382545.5	NP_000208.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNA1	ENST00000382545.5 link	c.114C>T	p.Arg38Arg	synonymous_variant	Exon 2 of 2	4	NM_000217.3	ENSP00000371985.3

Frequencies

GnomAD3 genomes

AF:

0.000171

AC:

AN:

152158

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

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:

0.000353

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000235

AC:

AN:

251068

AF XY:

0.000258

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000260

Gnomad ASJ exome

AF:

0.0000993

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000344

Gnomad OTH exome

AF:

0.00114

GnomAD4 exome

AF:

0.000215

AC:

314

AN:

1461848

Hom.:

Cov.:

AF XY:

0.000221

AC XY:

161

AN XY:

727230

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.000179

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.0000383

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000812

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53378

Middle Eastern (MID)

AF:

0.00243

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.000238

AC:

265

AN:

1112012

Other (OTH)

AF:

0.000315

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.482

Heterozygous variant carriers

105

131

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.000171

AC:

AN:

152276

Hom.:

Cov.:

AF XY:

0.000175

AC XY:

AN XY:

74454

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41564

American (AMR)

AF:

0.000131

AC:

AN:

15302

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5168

South Asian (SAS)

AF:

0.00

AC:

AN:

4816

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10614

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000353

AC:

AN:

68022

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000360

Hom.:

Bravo

AF:

0.000196

EpiCase

AF:

0.000491

EpiControl

AF:

0.000652

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Benign:3

Sep 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

KCNA1: BP4, BP7

Mar 04, 2019

Athena Diagnostics

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Breakthrough Genomics, Breakthrough Genomics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:not provided

Episodic ataxia type 1

Benign:2

Feb 04, 2022

Fulgent Genetics, Fulgent Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Jan 14, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.38

CADD

Benign

(source)

DANN

Benign

0.80

PhyloP100

-0.42

Mutation Taster

=96/4

polymorphism

(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

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over