rs3810472

chr20-63406707-C-T

Variant summary

Our verdict is Benign. Variant got -21 ACMG points: 0P and 21B. BP4_Strong BP6_Very_Strong BP7 BS1 BS2

The NM_172107.4(KCNQ2):c.2556G>A(p.Pro852=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000728 in 1,602,394 control chromosomes in the GnomAD database, including 27 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.00028 (1 hom., cov: 33)
  • Exomes 𝑓: 0.00078 (26 hom.)
• Consequence: KCNQ2 NM_172107.4 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:4
• Conservation: PhyloP100: -2.40

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]

ACMG classification

Verdict is Benign. Variant got -21 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.81).
• BP6: Variant 20-63406707-C-T is Benign according to our data. Variant chr20-63406707-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 138034.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=-2.39 with no splicing effect.
• BS1: Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.000276 (42/152356) while in subpopulation EAS AF= 0.0079 (41/5188). AF 95% confidence interval is 0.00599. There are 1 homozygotes in gnomad4. There are 23 alleles in male gnomad4 subpopulation. This position pass quality control queck.
• BS2: High AC in GnomAd at 42 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ2	NM_172107.4	c.2556G>A	p.Pro852=	synonymous_variant	17/17	ENST00000359125.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ2	ENST00000359125.7	c.2556G>A	p.Pro852=	synonymous_variant	17/17	1	NM_172107.4	A1

Frequencies

GnomAD3 genomes AF: 0.000276 AC: 42 AN: 152238 Hom.: 1 Cov.: 33

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00788

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

GnomAD3 exomes AF: 0.000166 AC: 37 AN: 223434 Hom.: 3 AF XY: 0.000162 AC XY: 20 AN XY: 123232

Gnomad AFR exome AF: 0.0000780

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00208

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000181

GnomAD4 exome AF: 0.000776 AC: 1125 AN: 1450038 Hom.: 26 Cov.: 30 AF XY: 0.000767 AC XY: 553 AN XY: 720808

Gnomad4 AFR exome AF: 0.0000300

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0280

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000202

Gnomad4 NFE exome AF: 0.0000135

Gnomad4 OTH exome AF: 0.000184

GnomAD4 genome AF: 0.000276 AC: 42 AN: 152356 Hom.: 1 Cov.: 33 AF XY: 0.000309 AC XY: 23 AN XY: 74500

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00790

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000174 Hom.: 1

Bravo AF: 0.0000680

Asia WGS AF: 0.00202 AC: 7 AN: 3478

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:2

Benign, criteria provided, single submitter	clinical testing	GeneDx	Feb 06, 2014	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Likely benign, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jul 12, 2016	- -

Inborn genetic diseases Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 07, 2018

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Early infantile epileptic encephalopathy with suppression bursts Benign:1

Benign, criteria provided, single submitter

clinical testing

Invitae

Jan 17, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.81
Cadd	Benign	6.3
Dann	Benign	0.72

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

LitVar

Other links and lift over

dbSNP: rs3810472; hg19: chr20-62038060; COSMIC: COSV60544711; COSMIC: COSV60544711;