rs780770793

chr20-63445326-G-A

Variant summary

Our verdict is Benign. Variant got -19 ACMG points: 0P and 19B. BP4_Moderate BP6_Very_Strong BP7 BS1 BS2

The NM_172107.4(KCNQ2):c.426C>T(p.Phe142=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000638 in 1,613,872 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 34)
  • Exomes 𝑓: 0.000068 (1 hom.)
• Consequence: KCNQ2 NM_172107.4 synonymous
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:2
• Conservation: PhyloP100: -1.84

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 -19 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.46).
• BP6: Variant 20-63445326-G-A is Benign according to our data. Variant chr20-63445326-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 380122.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=-1.84 with no splicing effect.
• BS1: Variant frequency is greater than expected in population sas. gnomad4_exome allele frequency = 0.0000684 (100/1461512) while in subpopulation SAS AF= 0.000649 (56/86254). AF 95% confidence interval is 0.000513. There are 1 homozygotes in gnomad4_exome. There are 61 alleles in male gnomad4_exome subpopulation. Median coverage is 32. This position pass quality control queck.
• BS2: High AC in GnomAdExome at 38 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ2	NM_172107.4	c.426C>T	p.Phe142=	synonymous_variant	3/17	ENST00000359125.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ2	ENST00000359125.7	c.426C>T	p.Phe142=	synonymous_variant	3/17	1	NM_172107.4	A1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152242 Hom.: 0 Cov.: 34

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000414

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000152 AC: 38 AN: 250780 Hom.: 0 AF XY: 0.000162 AC XY: 22 AN XY: 135778

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000145

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.000817

Gnomad FIN exome AF: 0.000231

Gnomad NFE exome AF: 0.0000265

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000684 AC: 100 AN: 1461512 Hom.: 1 Cov.: 32 AF XY: 0.0000839 AC XY: 61 AN XY: 727048

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.000112

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.000649

Gnomad4 FIN exome AF: 0.000301

Gnomad4 NFE exome AF: 0.0000153

Gnomad4 OTH exome AF: 0.0000662

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152360 Hom.: 0 Cov.: 34 AF XY: 0.0000134 AC XY: 1 AN XY: 74508

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000653

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000414

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Likely benign

Submissions summary: Benign:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:1

Likely benign, criteria provided, single submitter

clinical testing

GeneDx

Sep 15, 2016

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. -

Early infantile epileptic encephalopathy with suppression bursts Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Dec 22, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.46
Cadd	Benign	6.9
Dann	Benign	0.88

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: rs780770793; hg19: chr20-62076679; COSMIC: COSV60438733; COSMIC: COSV60438733;