rs370174915

chr20-63442468-A-G

Variant summary

Our verdict is Benign. Variant got -20 ACMG points: 0P and 20B. BP4_Strong BP6_Very_Strong BS1 BS2

The NM_172107.4(KCNQ2):c.754T>C(p.Leu252=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000109 in 1,613,790 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.00014 (0 hom., cov: 29)
  • Exomes 𝑓: 0.00011 (3 hom.)
• Consequence: KCNQ2 NM_172107.4 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:4
• Conservation: PhyloP100: 0.0510

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 -20 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.56).
• BP6: Variant 20-63442468-A-G is Benign according to our data. Variant chr20-63442468-A-G is described in ClinVar as [Likely_benign]. Clinvar id is 138016.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr20-63442468-A-G is described in Lovd as [Likely_benign].
• BS1: Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.000138 (21/152056) while in subpopulation EAS AF= 0.00155 (8/5164). AF 95% confidence interval is 0.00077. There are 0 homozygotes in gnomad4. There are 6 alleles in male gnomad4 subpopulation. This position pass quality control queck.
• BS2: High AC in GnomAd at 18 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ2	NM_172107.4	c.754T>C	p.Leu252=	synonymous_variant	5/17	ENST00000359125.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ2	ENST00000359125.7	c.754T>C	p.Leu252=	synonymous_variant	5/17	1	NM_172107.4	A1

Frequencies

GnomAD3 genomes AF: 0.000118 AC: 18 AN: 151938 Hom.: 0 Cov.: 29

Gnomad AFR AF: 0.0000969

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000327

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00155

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.000479

GnomAD3 exomes AF: 0.000119 AC: 30 AN: 251406 Hom.: 0 AF XY: 0.0000957 AC XY: 13 AN XY: 135880

Gnomad AFR exome AF: 0.000123

Gnomad AMR exome AF: 0.000116

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000870

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00114

GnomAD4 exome AF: 0.000106 AC: 155 AN: 1461734 Hom.: 3 Cov.: 32 AF XY: 0.0000798 AC XY: 58 AN XY: 727172

Gnomad4 AFR exome AF: 0.0000896

Gnomad4 AMR exome AF: 0.0000894

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000932

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000719

Gnomad4 OTH exome AF: 0.00169

GnomAD4 genome AF: 0.000138 AC: 21 AN: 152056 Hom.: 0 Cov.: 29 AF XY: 0.0000807 AC XY: 6 AN XY: 74338

Gnomad4 AFR AF: 0.0000966

Gnomad4 AMR AF: 0.000327

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00155

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00190

Alfa AF: 0.000217 Hom.: 0

Bravo AF: 0.000117

Asia WGS AF: 0.00375 AC: 13 AN: 3478

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:1

Benign, criteria provided, single submitter

clinical testing

GeneDx

Jul 09, 2013

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. -

Inborn genetic diseases Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 02, 2016

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. -

KCNQ2-related disorder Benign:1

Likely benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Oct 04, 2019

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Early infantile epileptic encephalopathy with suppression bursts Benign:1

Benign, criteria provided, single submitter

clinical testing

Invitae

Jan 22, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.56
Cadd	Benign	5.3
Dann	Benign	0.90

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: rs370174915; hg19: chr20-62073821;