chr12-4912262-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2PP2PP3_Strong

The NM_000217.3(KCNA1):​c.884G>T​(p.Arg295Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,822 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging 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. R295H) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 29)
Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

KCNA1
NM_000217.3 missense

Scores

17
1
1

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 9.93
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]

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ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
PP2
Missense variant in gene, where missense usually causes diseases (based on misZ statistic), KCNA1. . Gene score misZ 3.3255 (greater than the threshold 3.09). Trascript score misZ 3.8671 (greater than threshold 3.09). GenCC has associacion of gene with episodic kinesigenic dyskinesia 1, episodic ataxia type 1, developmental and epileptic encephalopathy, isolated autosomal dominant hypomagnesemia, Glaudemans type.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.961

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE UniProt
KCNA1NM_000217.3 linkuse as main transcriptc.884G>T p.Arg295Leu missense_variant 2/2 ENST00000382545.5

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Appris UniProt
KCNA1ENST00000382545.5 linkuse as main transcriptc.884G>T p.Arg295Leu missense_variant 2/24 NM_000217.3 P1
ENST00000640877.1 linkuse as main transcriptn.606+1790G>T intron_variant, non_coding_transcript_variant 5

Frequencies

GnomAD3 genomes
Cov.:
29
GnomAD3 exomes
AF:
0.00000399
AC:
1
AN:
250644
Hom.:
0
AF XY:
0.00000738
AC XY:
1
AN XY:
135488
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 SAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000885
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
6.84e-7
AC:
1
AN:
1461822
Hom.:
0
Cov.:
42
AF XY:
0.00000138
AC XY:
1
AN XY:
727212
show subpopulations
Gnomad4 AFR exome
AF:
0.00
Gnomad4 AMR exome
AF:
0.00
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.00
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
8.99e-7
Gnomad4 OTH exome
AF:
0.00
GnomAD4 genome
Cov.:
29
Alfa
AF:
0.0000329
Hom.:
0
Bravo
AF:
0.00000378
ExAC
AF:
0.00000824
AC:
1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
1.0
BayesDel_addAF
Pathogenic
0.57
D
BayesDel_noAF
Pathogenic
0.58
CADD
Pathogenic
34
DANN
Uncertain
1.0
DEOGEN2
Pathogenic
0.99
D
Eigen
Pathogenic
1.1
Eigen_PC
Pathogenic
0.99
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Pathogenic
1.0
D
M_CAP
Pathogenic
0.85
D
MetaRNN
Pathogenic
0.96
D
MetaSVM
Pathogenic
1.0
D
MutationAssessor
Pathogenic
3.5
H
MutationTaster
Benign
1.0
D
PrimateAI
Pathogenic
0.87
D
PROVEAN
Pathogenic
-6.8
D
REVEL
Pathogenic
0.96
Sift
Pathogenic
0.0
D
Sift4G
Pathogenic
0.0010
D
Polyphen
1.0
D
Vest4
0.92
MutPred
0.74
Loss of MoRF binding (P = 0.0202);
MVP
0.99
MPC
2.6
ClinPred
0.99
D
GERP RS
5.1
Varity_R
0.95
gMVP
0.99

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Other links and lift over

dbSNP: rs778463081; hg19: chr12-5021428; API