20-63407308-G-T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 3P and 1B. PM2PP2BP4

The NM_172107.4(KCNQ2):​c.1955C>A​(p.Pro652Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000693 in 1,443,682 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign 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. P652R) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 33)
Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

KCNQ2
NM_172107.4 missense

Scores

3
4
11

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 2.09

Publications

2 publications found
Variant links:
Genes affected
KCNQ2 (HGNC:6296): (potassium voltage-gated channel subfamily Q member 2) The M channel is a slowly activating and deactivating potassium channel that plays a critical role in the regulation of neuronal excitability. The M channel is formed by the association of the protein encoded by this gene and a related protein encoded by the KCNQ3 gene, both integral membrane proteins. M channel currents are inhibited by M1 muscarinic acetylcholine receptors and activated by retigabine, a novel anti-convulsant drug. Defects in this gene are a cause of benign familial neonatal convulsions type 1 (BFNC), also known as epilepsy, benign neonatal type 1 (EBN1). At least five transcript variants encoding five different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
KCNQ2 Gene-Disease associations (from GenCC):
  • complex neurodevelopmental disorder
    Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
  • developmental and epileptic encephalopathy, 7
    Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P
  • neonatal encephalopathy with non-epileptic myoclonus
    Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
  • neonatal-onset developmental and epileptic encephalopathy
    Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
  • seizures, benign familial neonatal, 1
    Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
  • seizures, benign familial neonatal, 2
    Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
  • benign familial infantile epilepsy
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • benign familial neonatal-infantile seizures
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • benign neonatal seizures
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • malignant migrating partial seizures of infancy
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
PP2
Missense variant in the KCNQ2 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 319 curated pathogenic missense variants (we use a threshold of 10). The gene has 78 curated benign missense variants. Gene score misZ: 4.0411 (above the threshold of 3.09). Trascript score misZ: 3.6968 (above the threshold of 3.09). GenCC associations: The gene is linked to benign familial infantile epilepsy, malignant migrating partial seizures of infancy, developmental and epileptic encephalopathy, 7, benign familial neonatal-infantile seizures, benign neonatal seizures, neonatal-onset developmental and epileptic encephalopathy, complex neurodevelopmental disorder, seizures, benign familial neonatal, 2, seizures, benign familial neonatal, 1, neonatal encephalopathy with non-epileptic myoclonus.
BP4
Computational evidence support a benign effect (MetaRNN=0.2859884).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
KCNQ2NM_172107.4 linkc.1955C>A p.Pro652Gln missense_variant Exon 17 of 17 ENST00000359125.7 NP_742105.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
KCNQ2ENST00000359125.7 linkc.1955C>A p.Pro652Gln missense_variant Exon 17 of 17 1 NM_172107.4 ENSP00000352035.2

Frequencies

GnomAD3 genomes
Cov.:
33
GnomAD2 exomes
AF:
0.00000424
AC:
1
AN:
236050
AF XY:
0.00000772
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:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
6.93e-7
AC:
1
AN:
1443682
Hom.:
0
Cov.:
36
AF XY:
0.00000139
AC XY:
1
AN XY:
718028
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33438
American (AMR)
AF:
0.00
AC:
0
AN:
44604
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26096
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39598
South Asian (SAS)
AF:
0.0000116
AC:
1
AN:
86116
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
38120
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5752
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1109818
Other (OTH)
AF:
0.00
AC:
0
AN:
60140
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
Cov.:
33
ExAC
AF:
0.00000826
AC:
1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.091
BayesDel_addAF
Uncertain
0.069
T
BayesDel_noAF
Uncertain
-0.040
CADD
Benign
22
DANN
Benign
0.26
DEOGEN2
Benign
0.0
.;T;T;T;T;T;T;.;.
Eigen
Benign
-0.37
Eigen_PC
Benign
-0.20
FATHMM_MKL
Benign
0.75
D
LIST_S2
Uncertain
0.90
D;D;D;D;D;D;D;D;D
M_CAP
Pathogenic
0.50
D
MetaRNN
Benign
0.29
T;T;T;T;T;T;T;T;T
MetaSVM
Pathogenic
1.1
D
MutationAssessor
Benign
0.0
.;.;.;.;.;N;.;.;.
PhyloP100
2.1
PrimateAI
Uncertain
0.51
T
PROVEAN
Benign
0.0
.;.;.;N;.;N;.;N;.
REVEL
Benign
0.0
Sift
Pathogenic
0.0
.;.;.;T;.;T;.;T;.
Sift4G
Benign
0.96
T;T;T;T;.;T;T;T;T
Vest4
0.11
ClinPred
0.13
T
GERP RS
5.1
Varity_R
0.12
gMVP
0.33
Mutation Taster
=87/13
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.020
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: rs770730662; hg19: chr20-62038661; COSMIC: COSV60550914; COSMIC: COSV60550914; API