rs150982653

chr20-63407214-G-Achr20-63407214-G-T

Variant summary

Our verdict is Benign. Variant got -17 ACMG points: 0P and 17B. BP4_Strong BP6_Very_Strong BP7 BS2

The NM_172107.4(KCNQ2):c.2049C>T(p.His683=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000108 in 1,604,976 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 Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.00015 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00010 (0 hom.)
• Consequence: KCNQ2 NM_172107.4 synonymous
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:3
• Conservation: PhyloP100: -2.35

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 -17 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.86).
• BP6: Variant 20-63407214-G-A is Benign according to our data. Variant chr20-63407214-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 339331.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=-2.35 with no splicing effect.
• BS2: High AC in GnomAd at 23 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ2	NM_172107.4	c.2049C>T	p.His683=	synonymous_variant	17/17	ENST00000359125.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ2	ENST00000359125.7	c.2049C>T	p.His683=	synonymous_variant	17/17	1	NM_172107.4	A1

Frequencies

GnomAD3 genomes AF: 0.000151 AC: 23 AN: 152222 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000482

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000131

Gnomad ASJ AF: 0.00403

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.0000941

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.000478

GnomAD3 exomes AF: 0.000189 AC: 45 AN: 238616 Hom.: 0 AF XY: 0.000168 AC XY: 22 AN XY: 131286

Gnomad AFR exome AF: 0.0000672

Gnomad AMR exome AF: 0.0000583

Gnomad ASJ exome AF: 0.00324

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.000127

Gnomad NFE exome AF: 0.0000640

Gnomad OTH exome AF: 0.000169

GnomAD4 exome AF: 0.000103 AC: 150 AN: 1452754 Hom.: 0 Cov.: 36 AF XY: 0.0000982 AC XY: 71 AN XY: 723028

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.0000895

Gnomad4 ASJ exome AF: 0.00272

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000666

Gnomad4 NFE exome AF: 0.0000531

Gnomad4 OTH exome AF: 0.000199

GnomAD4 genome AF: 0.000151 AC: 23 AN: 152222 Hom.: 0 Cov.: 33 AF XY: 0.000121 AC XY: 9 AN XY: 74368

Gnomad4 AFR AF: 0.0000482

Gnomad4 AMR AF: 0.000131

Gnomad4 ASJ AF: 0.00403

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.0000941

Gnomad4 NFE AF: 0.0000441

Gnomad4 OTH AF: 0.000478

Alfa AF: 0.000238 Hom.: 0

Bravo AF: 0.000113

ClinVar

Significance: Likely benign

Submissions summary: Benign:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 26, 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

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Dec 11, 2023

- -

not provided Benign:1

Likely benign, criteria provided, single submitter

clinical testing

GeneDx

Mar 02, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.86
Cadd	Benign	1.2
Dann	Benign	0.55

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: rs150982653; hg19: chr20-62038567; COSMIC: COSV60543029; COSMIC: COSV60543029;