Genetic Variant KCNB1:p.Gly846Glu (chr20-49373023-C-T) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_004975.4(KCNB1):c.2537G>A(p.Gly846Glu) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,504 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G846V) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

KCNB1
NM_004975.4 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 5.17

Publications

0 publications found

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 Gene-Disease associations (from GenCC):

complex neurodevelopmental disorder
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
developmental and epileptic encephalopathy, 26
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae)
undetermined early-onset epileptic encephalopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

KCNB1 links:

ENSG00000290421 (HGNC:):

ENSG00000290421 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNB1	NM_004975.4 link	c.2537G>A	p.Gly846Glu	missense_variant	Exon 2 of 2	ENST00000371741.6	NP_004966.1	Q14721
KCNB1	XM_011528799.3 link	c.2537G>A	p.Gly846Glu	missense_variant	Exon 3 of 3		XP_011527101.1	Q14721
LOC105372649	XR_001754659.2 link	n.1201+40999C>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.2537G>A	p.Gly846Glu	missense_variant	Exon 2 of 2	1	NM_004975.4	ENSP00000360806.3		Q14721

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461504

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727076

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33466

American (AMR)

AF:

0.00

AC:

AN:

44702

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26114

East Asian (EAS)

AF:

0.00

AC:

AN:

39690

South Asian (SAS)

AF:

0.00

AC:

AN:

86204

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53406

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5706

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111834

Other (OTH)

AF:

0.00

AC:

AN:

60382

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.15

BayesDel_addAF

Pathogenic

0.31

BayesDel_noAF

Pathogenic

0.21

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.65

D;D

Eigen

Uncertain

0.50

Eigen_PC

Uncertain

0.46

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.79

.;T

M_CAP

Uncertain

0.25

MetaRNN

Uncertain

0.71

D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Benign

0.81

L;L

PhyloP100

5.2

PrimateAI

Uncertain

0.59

PROVEAN

Uncertain

-2.5

D;.

REVEL

Pathogenic

0.71

Sift

Uncertain

0.0010

D;.

Sift4G

Uncertain

0.011

D;D

Polyphen

1.0

D;D

Vest4

0.45

MutPred

0.51

Gain of solvent accessibility (P = 0.0012);Gain of solvent accessibility (P = 0.0012);

MVP

0.66

MPC

0.75

ClinPred

0.77

GERP RS

5.0

Varity_R

0.33

gMVP

0.84

Mutation Taster

=75/25

polymorphism

(source)

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

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20-49373023-C-T

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over