rs28933381

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

8
3
8

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

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

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
KCNA1NM_000217.3 linkc.724G>A p.Ala242Thr missense_variant Exon 2 of 2 ENST00000382545.5 NP_000208.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
KCNA1ENST00000382545.5 linkc.724G>A p.Ala242Thr missense_variant Exon 2 of 2 4 NM_000217.3 ENSP00000371985.3

Frequencies

GnomAD3 genomes
AF:
0.00000658
AC:
1
AN:
151894
Hom.:
0
Cov.:
31
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.:
60
GnomAD4 genome
AF:
0.00000658
AC:
1
AN:
151894
Hom.:
0
Cov.:
31
AF XY:
0.00
AC XY:
0
AN XY:
74164
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41354
American (AMR)
AF:
0.0000655
AC:
1
AN:
15256
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5162
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4790
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10560
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
67996
Other (OTH)
AF:
0.00
AC:
0
AN:
2080
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.525
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.00
Hom.:
0

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.31
BayesDel_addAF
Pathogenic
0.24
D
BayesDel_noAF
Uncertain
0.11
CADD
Uncertain
25
DANN
Uncertain
0.99
DEOGEN2
Pathogenic
0.92
D
Eigen
Benign
-0.075
Eigen_PC
Benign
0.058
FATHMM_MKL
Pathogenic
0.98
D
LIST_S2
Benign
0.86
D
M_CAP
Pathogenic
0.36
D
MetaRNN
Pathogenic
0.78
D
MetaSVM
Pathogenic
0.95
D
MutationAssessor
Benign
0.55
N
PhyloP100
6.8
PrimateAI
Pathogenic
0.83
D
PROVEAN
Uncertain
-3.2
D
REVEL
Pathogenic
0.75
Sift
Benign
0.056
T
Sift4G
Benign
0.20
T
Polyphen
0.28
B
Vest4
0.66
MutPred
0.70
Gain of catalytic residue at K246 (P = 0.0067);
MVP
0.96
MPC
1.7
ClinPred
0.98
D
GERP RS
4.1
PromoterAI
-0.013
Neutral
Varity_R
0.41
gMVP
0.83
Mutation Taster
=41/59
disease causing

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

Other links and lift over

dbSNP: rs28933381; hg19: chr12-5021268; COSMIC: COSV101230380; COSMIC: COSV101230380; API