rs771845478

Variant summary

Our verdict is Benign. Variant got -10 ACMG points: 0P and 10B. BP4_StrongBP7BS1_SupportingBS2

The NM_172107.4(KCNQ2):​c.1347C>T​(p.Gly449Gly) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000735 in 1,605,116 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000053 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000076 ( 0 hom. )

Consequence

KCNQ2
NM_172107.4 synonymous

Scores

2

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:1

Conservation

PhyloP100: -0.698
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]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -10 ACMG points.

BP4
Computational evidence support a benign effect (BayesDel_noAF=-0.54).
BP7
Synonymous conserved (PhyloP=-0.698 with no splicing effect.
BS1
Variant frequency is greater than expected in population eas. gnomad4_exome allele frequency = 0.0000757 (110/1452814) while in subpopulation EAS AF= 0.000202 (8/39696). AF 95% confidence interval is 0.0000993. There are 0 homozygotes in gnomad4_exome. There are 59 alleles in male gnomad4_exome subpopulation. Median coverage is 35. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
BS2
High AC in GnomAd4 at 8 AD gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
KCNQ2NM_172107.4 linkc.1347C>T p.Gly449Gly synonymous_variant Exon 13 of 17 ENST00000359125.7 NP_742105.1 O43526-1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
KCNQ2ENST00000359125.7 linkc.1347C>T p.Gly449Gly synonymous_variant Exon 13 of 17 1 NM_172107.4 ENSP00000352035.2 O43526-1

Frequencies

GnomAD3 genomes
AF:
0.0000526
AC:
8
AN:
152184
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0000241
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000654
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.000193
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000735
Gnomad OTH
AF:
0.00
GnomAD3 exomes
AF:
0.0000500
AC:
12
AN:
239998
Hom.:
0
AF XY:
0.0000457
AC XY:
6
AN XY:
131256
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.000274
Gnomad SAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000640
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000757
AC:
110
AN:
1452814
Hom.:
0
Cov.:
35
AF XY:
0.0000816
AC XY:
59
AN XY:
723184
show subpopulations
Gnomad4 AFR exome
AF:
0.000149
Gnomad4 AMR exome
AF:
0.00
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.000202
Gnomad4 SAS exome
AF:
0.00
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.0000845
Gnomad4 OTH exome
AF:
0.0000497
GnomAD4 genome
AF:
0.0000525
AC:
8
AN:
152302
Hom.:
0
Cov.:
32
AF XY:
0.0000269
AC XY:
2
AN XY:
74464
show subpopulations
Gnomad4 AFR
AF:
0.0000241
Gnomad4 AMR
AF:
0.0000653
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.000194
Gnomad4 SAS
AF:
0.00
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.0000735
Gnomad4 OTH
AF:
0.00
Alfa
AF:
0.0000285
Hom.:
0
Bravo
AF:
0.0000567

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:3Benign:1
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not provided Uncertain:2
Uncertain significance, criteria provided, single submitterclinical testingGeneDxJun 26, 2017A variant of uncertain significance has been identified in the KCNQ2 gene. The c.1347 C>T variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. The c.1347 C>T variant is observed in 1/8434 (0.01%) alleles from individuals of East Asian background (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). Several in-silico splice prediction models predict that c.1347 C>T creates a cryptic donor site which may supplant the natural donor site and lead to abnormal gene splicing. However, in the absence of RNA/functional studies, the actual effect of this sequence change in this individual is unknown. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic variant or a rare benign variant. -
Uncertain significance, criteria provided, single submitterclinical testingEurofins Ntd Llc (ga)Apr 12, 2018- -
Seizures, benign familial neonatal, 1;C3150986:Developmental and epileptic encephalopathy, 7 Uncertain:1
Uncertain significance, criteria provided, single submitterclinical testingFulgent Genetics, Fulgent GeneticsOct 31, 2018- -
Early infantile epileptic encephalopathy with suppression bursts Benign:1
Likely benign, criteria provided, single submitterclinical testingLabcorp Genetics (formerly Invitae), LabcorpDec 16, 2024- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_noAF
Benign
-0.54
CADD
Benign
12
DANN
Benign
0.76

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.11
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: rs771845478; hg19: chr20-62046434; API