chr12-4911438-G-C

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 1P and 7B. PP2BP4_ModerateBP6BS1

The NM_000217.3(KCNA1):c.60G>C(p.Gln20His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000434 in 1,613,612 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 13/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q20R) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00018 ( 0 hom., cov: 31)

Exomes 𝑓: 0.00046 ( 1 hom. )

Consequence

KCNA1
NM_000217.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:2

Conservation

PhyloP100: 1.51

Publications

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

KCNA1 links:

ENSG00000256654 (HGNC:):

ENSG00000256654 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -6 ACMG points.

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.

BP4

Computational evidence support a benign effect (MetaRNN=0.13596153).

BP6

Variant 12-4911438-G-C is Benign according to our data. Variant chr12-4911438-G-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 447612.

BS1

Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.000184 (28/152160) while in subpopulation NFE AF = 0.000368 (25/68022). AF 95% confidence interval is 0.000255. There are 0 homozygotes in GnomAd4. There are 12 alleles in the male GnomAd4 subpopulation. Median coverage is 31. This position passed quality control check.

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.60G>C	p.Gln20His	missense	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.60G>C	p.Gln20His	missense	Exon 2 of 2	ENSP00000371985.3	Q09470
ENSG00000256654	ENST00000541095.1	TSL:3	n.105+966G>C		intron	N/A
KCNA1	ENST00000543874.3	TSL:2	n.105+966G>C		intron	N/A

Frequencies

GnomAD3 genomes

AF:

0.000184

AC:

AN:

152160

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.000368

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000113

AC:

AN:

248316

AF XY:

0.0000963

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000241

Gnomad OTH exome

AF:

0.000165

GnomAD4 exome

AF:

0.000460

AC:

672

AN:

1461452

Hom.:

Cov.:

AF XY:

0.000444

AC XY:

323

AN XY:

727072

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33476

American (AMR)

AF:

0.00

AC:

AN:

44700

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26110

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.0000232

AC:

AN:

86240

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53166

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.000581

AC:

646

AN:

1111914

Other (OTH)

AF:

0.000397

AC:

AN:

60382

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.472

Heterozygous variant carriers

131

174

218

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

128

160

<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:

0.000184

AC:

AN:

152160

Hom.:

Cov.:

AF XY:

0.000161

AC XY:

AN XY:

74332

show subpopulations

African (AFR)

AF:

0.0000724

AC:

AN:

41444

American (AMR)

AF:

0.00

AC:

AN:

15284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5180

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000368

AC:

AN:

68022

Other (OTH)

AF:

0.00

AC:

AN:

2094

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:

0.000225

Hom.:

Bravo

AF:

0.000170

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000519

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000349

AC:

ExAC

AF:

0.000107

AC:

EpiCase

AF:

0.000491

EpiControl

AF:

0.000474

ClinVar

ClinVar submissions

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

Episodic ataxia type 1 (2)

not provided (2)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.11

BayesDel_addAF

Benign

-0.13

BayesDel_noAF

Benign

-0.10

CADD

Benign

(source)

DANN

Benign

0.93

DEOGEN2

Benign

0.41

Eigen

Benign

-0.17

Eigen_PC

Benign

-0.066

FATHMM_MKL

Uncertain

0.91

LIST_S2

Benign

0.85

M_CAP

Uncertain

0.12

MetaRNN

Benign

0.14

MetaSVM

Uncertain

0.46

MutationAssessor

Benign

2.0

PhyloP100

1.5

PrimateAI

Uncertain

0.62

PROVEAN

Benign

-1.0

REVEL

Uncertain

0.38

Sift

Benign

0.24

Sift4G

Benign

0.20

Polyphen

0.010

Vest4

0.23

MutPred

0.27

Gain of catalytic residue at Y24 (P = 0.0028)

MVP

0.91

MPC

1.1

ClinPred

0.056

GERP RS

2.8

Varity_R

0.12

gMVP

0.72

Mutation Taster

=31/69

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over