20-49373833-G-T

Position:

chr20-49373833-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2PP2BP4_Moderate

The NM_004975.4(KCNB1):c.1727C>A(p.Thr576Lys) variant causes a missense change. The variant allele was found at a frequency of 0.00000124 in 1,613,958 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

KCNB1
NM_004975.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 4.16

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 Uncertain_significance. Variant got 1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

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=0.17790985).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNB1	NM_004975.4 linkuse as main transcript	c.1727C>A	p.Thr576Lys	missense_variant	2/2	ENST00000371741.6	NP_004966.1	Q14721
KCNB1	XM_011528799.3 linkuse as main transcript	c.1727C>A	p.Thr576Lys	missense_variant	3/3		XP_011527101.1	Q14721
LOC105372649	XR_001754659.2 linkuse as main transcript	n.1201+41809G>T		intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	UniProt
KCNB1	ENST00000371741.6 linkuse as main transcript	c.1727C>A	p.Thr576Lys	missense_variant	2/2	1	NM_004975.4	ENSP00000360806.3	Q14721
KCNB1	ENST00000635465.1 linkuse as main transcript	c.1727C>A	p.Thr576Lys	missense_variant	3/3	1		ENSP00000489193.1	Q14721
KCNB1	ENST00000635878.1 linkuse as main transcript	c.97-74450C>A		intron_variant		5		ENSP00000489908.1	A0A1B0GU02
ENSG00000290421	ENST00000637341.1 linkuse as main transcript	n.206+41809G>T		intron_variant		5

Frequencies

GnomAD3 genomes

AF:

0.00000657

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461840

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727220

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152118

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74326

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:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Developmental and epileptic encephalopathy, 26

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 27, 2021

In summary, this variant is a novel missense change that is not predicted to affect protein function. There is no indication that it causes disease, but the available evidence is currently insufficient to prove that conclusively. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a KCNB1-related disease. This sequence change replaces threonine with lysine at codon 576 of the KCNB1 protein (p.Thr576Lys). The threonine residue is moderately conserved and there is a moderate physicochemical difference between threonine and lysine. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.092

BayesDel_addAF

Benign

-0.19

BayesDel_noAF

Benign

-0.51

CADD

Benign

DANN

Benign

0.94

DEOGEN2

Benign

0.22

T;T

Eigen

Benign

0.0077

Eigen_PC

Uncertain

0.22

FATHMM_MKL

Uncertain

0.95

LIST_S2

Benign

0.60

.;T

M_CAP

Benign

0.0040

MetaRNN

Benign

0.18

T;T

MetaSVM

Benign

-1.0

MutationAssessor

Benign

1.0

L;L

PrimateAI

Uncertain

0.53

PROVEAN

Benign

0.030

N;.

REVEL

Benign

0.16

Sift

Benign

0.20

T;.

Sift4G

Benign

0.88

T;T

Polyphen

0.0040

B;B

Vest4

0.15

MutPred

0.50

Gain of ubiquitination at T576 (P = 0.001);Gain of ubiquitination at T576 (P = 0.001);

MVP

0.24

MPC

0.23

ClinPred

0.83

GERP RS

6.1

Varity_R

0.13

gMVP

0.38

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