chr20-49374193-C-T

Position:

chr20-49374193-C-T

Variant summary

Our verdict is Benign. Variant got -17 ACMG points: 1P and 18B. PP2BP4_ModerateBP6_Very_StrongBS1BS2

The NM_004975.4(KCNB1):c.1367G>A(p.Arg456Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000216 in 1,614,042 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R456G) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00011 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00023 ( 0 hom. )

Consequence

KCNB1
NM_004975.4 missense

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:5

Conservation

PhyloP100: 3.39

Variant links:

Genes affected

KCNB1 (HGNC:6231): (potassium voltage-gated channel subfamily B member 1) Voltage-gated potassium (Kv) channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has been shown to have human homolog(s). This gene encodes a member of the potassium channel, voltage-gated, shab-related subfamily. This member is a delayed rectifier potassium channel and its activity is modulated by some other family members. [provided by RefSeq, Jul 2008]

KCNB1 links:

(HGNC:):

links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -17 ACMG points.

PP2

Missense variant in gene, where missense usually causes diseases (based on misZ statistic), KCNB1. . Gene score misZ 4.269 (greater than the threshold 3.09). Trascript score misZ 5.3923 (greater than threshold 3.09). GenCC has associacion of gene with undetermined early-onset epileptic encephalopathy, complex neurodevelopmental disorder, developmental and epileptic encephalopathy, 26.

BP4

Computational evidence support a benign effect (MetaRNN=0.23682433).

BP6

Variant 20-49374193-C-T is Benign according to our data. Variant chr20-49374193-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 385978.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BS1

Variant frequency is greater than expected in population nfe. gnomad4_exome allele frequency = 0.000226 (331/1461850) while in subpopulation NFE AF= 0.000288 (320/1111996). AF 95% confidence interval is 0.000262. There are 0 homozygotes in gnomad4_exome. There are 166 alleles in male gnomad4_exome subpopulation. Median coverage is 33. This position pass quality control queck.

BS2

High AC in GnomAd4 at 17 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
KCNB1	NM_004975.4 linkuse as main transcript	c.1367G>A	p.Arg456Gln	missense_variant	2/2	ENST00000371741.6
LOC105372649	XR_001754659.2 linkuse as main transcript	n.1201+42169C>T		intron_variant, non_coding_transcript_variant
KCNB1	XM_011528799.3 linkuse as main transcript	c.1367G>A	p.Arg456Gln	missense_variant	3/3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris
KCNB1	ENST00000371741.6 linkuse as main transcript	c.1367G>A	p.Arg456Gln	missense_variant	2/2	1	NM_004975.4	P1
KCNB1	ENST00000635465.1 linkuse as main transcript	c.1367G>A	p.Arg456Gln	missense_variant	3/3	1		P1
	ENST00000637341.1 linkuse as main transcript	n.206+42169C>T		intron_variant, non_coding_transcript_variant		5
KCNB1	ENST00000635878.1 linkuse as main transcript	c.97-74810G>A		intron_variant		5

Frequencies

GnomAD3 genomes

AF:

0.000112

AC:

AN:

152192

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00219

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000192

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000191

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000115

AC:

AN:

251384

Hom.:

AF XY:

0.000118

AC XY:

AN XY:

135850

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000246

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000226

AC:

331

AN:

1461850

Hom.:

Cov.:

AF XY:

0.000228

AC XY:

166

AN XY:

727222

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000348

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.000288

Gnomad4 OTH exome

AF:

0.000132

GnomAD4 genome

AF:

0.000112

AC:

AN:

152192

Hom.:

Cov.:

AF XY:

0.0000807

AC XY:

AN XY:

74350

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000192

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000191

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000392

Hom.:

Bravo

AF:

0.000147

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000778

AC:

ExAC

AF:

0.0000906

AC:

EpiCase

AF:

0.000164

EpiControl

AF:

0.000237

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Benign:2

Likely benign, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Oct 01, 2023	KCNB1: BP5, BS1:Supporting -
Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Jun 02, 2021	- -

Developmental and epileptic encephalopathy, 26

Benign:1

Benign, criteria provided, single submitter

clinical testing

Invitae

Jan 19, 2024

- -

KCNB1-related disorder

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Nov 21, 2023

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). -

Inborn genetic diseases

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 20, 2023

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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.14

BayesDel_addAF

Uncertain

0.066

BayesDel_noAF

Pathogenic

0.15

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Benign

0.39

T;T

Eigen

Pathogenic

0.69

Eigen_PC

Pathogenic

0.70

FATHMM_MKL

Uncertain

0.94

LIST_S2

Pathogenic

0.98

.;D

M_CAP

Uncertain

0.20

MetaRNN

Benign

0.24

T;T

MetaSVM

Pathogenic

0.96

MutationAssessor

Uncertain

2.3

M;M

MutationTaster

Benign

1.0

PrimateAI

Benign

0.46

PROVEAN

Benign

-2.3

N;.

REVEL

Uncertain

0.57

Sift

Benign

0.041

D;.

Sift4G

Uncertain

0.024

D;D

Polyphen

1.0

D;D

Vest4

0.17

MVP

0.84

MPC

0.74

ClinPred

0.29

GERP RS

5.8

Varity_R

0.29

gMVP

0.78

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over