20-49373236-G-T

Variant names:

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 1P and 7B. PP2BP4_ModerateBP6BS2

The NM_004975.4(KCNB1):c.2324C>A(p.Pro775His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000991 in 1,614,006 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 Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00011 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000099 ( 1 hom. )

Consequence

KCNB1
NM_004975.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:1

Conservation

PhyloP100: 9.45

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:

ENSG00000290421 (HGNC:):

ENSG00000290421 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -6 ACMG points.

PP2

Missense variant in the KCNB1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 76 curated pathogenic missense variants (we use a threshold of 10). The gene has 110 curated benign missense variants. Gene score misZ: 4.269 (above the threshold of 3.09). Trascript score misZ: 5.3923 (above the threshold of 3.09). GenCC associations: The gene is linked to undetermined early-onset epileptic encephalopathy, complex neurodevelopmental disorder, developmental and epileptic encephalopathy, 26.

BP4

Computational evidence support a benign effect (MetaRNN=0.15990713).

BP6

Variant 20-49373236-G-T is Benign according to our data. Variant chr20-49373236-G-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 430040.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=2}.

BS2

High AC in GnomAd4 at 16 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNB1	NM_004975.4 link	c.2324C>A	p.Pro775His	missense_variant	Exon 2 of 2	ENST00000371741.6	NP_004966.1	Q14721
KCNB1	XM_011528799.3 link	c.2324C>A	p.Pro775His	missense_variant	Exon 3 of 3		XP_011527101.1	Q14721
LOC105372649	XR_001754659.2 link	n.1201+41212G>T		intron_variant	Intron 2 of 3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNB1	ENST00000371741.6 link	c.2324C>A	p.Pro775His	missense_variant	Exon 2 of 2	1	NM_004975.4	ENSP00000360806.3		Q14721

Frequencies

GnomAD3 genomes

AF:

0.000105

AC:

AN:

152118

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000206

Gnomad OTH

AF:

0.000479

GnomAD3 exomes

AF:

0.0000477

AC:

AN:

251358

Hom.:

AF XY:

0.0000442

AC XY:

AN XY:

135840

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

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:

0.0000792

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000985

AC:

144

AN:

1461888

Hom.:

Cov.:

AF XY:

0.000109

AC XY:

AN XY:

727242

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000504

Gnomad4 SAS exome

AF:

0.0000464

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.000108

Gnomad4 OTH exome

AF:

0.000248

GnomAD4 genome

AF:

0.000105

AC:

AN:

152118

Hom.:

Cov.:

AF XY:

0.000121

AC XY:

AN XY:

74298

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000206

Gnomad4 OTH

AF:

0.000479

Alfa

AF:

0.000109

Hom.:

Bravo

AF:

0.0000529

ExAC

AF:

0.0000330

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.000164

EpiControl

AF:

0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2

May 15, 2017

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The P775H variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. The P775H variant is observed in 3/66738 (0.004%) alleles from individuals of European background (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). This variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved in mammals; however, missense variants in nearby residues have not been reported in the Human Gene Mutation Database in association with KCNB1-related disorders (Stenson et al., 2014). In silico analysis is inconsistent in its predictions as to whether or not the variant is damaging to the protein structure/function. -

Jan 04, 2018

Eurofins Ntd Llc (ga)

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Developmental and epileptic encephalopathy, 26

Benign:1

Jan 22, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.086

BayesDel_addAF

Benign

-0.086

BayesDel_noAF

Uncertain

0.0

CADD

Uncertain

DANN

Uncertain

0.99

DEOGEN2

Benign

0.29

T;T

Eigen

Benign

0.15

Eigen_PC

Uncertain

0.31

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Benign

0.72

.;T

M_CAP

Benign

0.048

MetaRNN

Benign

0.16

T;T

MetaSVM

Uncertain

-0.013

MutationAssessor

Benign

0.69

N;N

PrimateAI

Benign

0.45

PROVEAN

Benign

-0.74

N;.

REVEL

Uncertain

0.38

Sift

Benign

0.043

D;.

Sift4G

Benign

0.25

T;T

Polyphen

0.016

B;B

Vest4

0.34

MutPred

0.097

Loss of glycosylation at P775 (P = 0.0076);Loss of glycosylation at P775 (P = 0.0076);

MVP

0.50

MPC

0.37

ClinPred

0.17

GERP RS

4.6

Varity_R

0.12

gMVP

0.31

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