rs145204452

chr8-132129802-C-T

Variant summary

Our verdict is Benign. Variant got -10 ACMG points: 0P and 10B. BP4_Strong BP6 BP7 BS2

The NM_004519.4(KCNQ3):c.2079G>A(p.Pro693=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000589 in 1,614,108 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 0.000059 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000059 (0 hom.)
• Consequence: KCNQ3 NM_004519.4 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:3
• Conservation: PhyloP100: -1.99

Genes affected

KCNQ3 (HGNC:6297): (potassium voltage-gated channel subfamily Q member 3) This gene encodes a protein that functions in the regulation of neuronal excitability. The encoded protein forms an M-channel by associating with the products of the related KCNQ2 or KCNQ5 genes, which both encode integral membrane proteins. M-channel currents are inhibited by M1 muscarinic acetylcholine receptors and are activated by retigabine, a novel anti-convulsant drug. Defects in this gene are a cause of benign familial neonatal convulsions type 2 (BFNC2), also known as epilepsy, benign neonatal type 2 (EBN2). Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, May 2014]

ACMG classification

Verdict is Benign. Variant got -10 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.79).
• BP6: Variant 8-132129802-C-T is Benign according to our data. Variant chr8-132129802-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 239950.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=1, Benign=1}.
• BP7: Synonymous conserved (PhyloP=-1.99 with no splicing effect.
• BS2: High AC in GnomAd at 9 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNQ3	NM_004519.4	c.2079G>A	p.Pro693=	synonymous_variant	15/15	ENST00000388996.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNQ3	ENST00000388996.10	c.2079G>A	p.Pro693=	synonymous_variant	15/15	1	NM_004519.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000592 AC: 9 AN: 152106 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000415

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00633

Gnomad NFE AF: 0.0000735

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000756 AC: 19 AN: 251430 Hom.: 0 AF XY: 0.0000736 AC XY: 10 AN XY: 135900

Gnomad AFR exome AF: 0.000123

Gnomad AMR exome AF: 0.0000578

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000653

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000114

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000588 AC: 86 AN: 1461884 Hom.: 0 Cov.: 32 AF XY: 0.0000674 AC XY: 49 AN XY: 727242

Gnomad4 AFR exome AF: 0.0000896

Gnomad4 AMR exome AF: 0.0000447

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000464

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000647

Gnomad4 OTH exome AF: 0.0000662

GnomAD4 genome AF: 0.0000591 AC: 9 AN: 152224 Hom.: 0 Cov.: 32 AF XY: 0.0000538 AC XY: 4 AN XY: 74414

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000415

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000735

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000154 Hom.: 0

Bravo AF: 0.0000756

EpiCase AF: 0.0000545

EpiControl AF: 0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:3

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Benign Neonatal Epilepsy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jun 14, 2016

- -

Seizures, benign familial neonatal, 2 Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Benign neonatal seizures Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Jan 31, 2024

- -

not provided Benign:1

Likely benign, criteria provided, single submitter

clinical testing

GeneDx

Mar 25, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.79
Cadd	Benign	0.056
Dann	Benign	0.35

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: rs145204452; hg19: chr8-133142049; COSMIC: COSV66472560;