20-49373087-G-C

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_004975.4(KCNB1):c.2473C>G(p.Pro825Ala) variant causes a missense change. The variant allele was found at a frequency of 0.00000186 in 1,613,984 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P825S) has been classified as Benign.

Frequency

Genomes: 𝑓 0.000013 ( 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: 6.42

Publications

9 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: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
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 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.13569397).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004975.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNB1	NM_004975.4	MANE Select	c.2473C>G	p.Pro825Ala	missense	Exon 2 of 2	NP_004966.1	Q14721

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
KCNB1	ENST00000371741.6	TSL:1 MANE Select	c.2473C>G	p.Pro825Ala	missense	Exon 2 of 2	ENSP00000360806.3	Q14721
KCNB1	ENST00000635465.1	TSL:1	c.2473C>G	p.Pro825Ala	missense	Exon 3 of 3	ENSP00000489193.1	Q14721
KCNB1	ENST00000635878.1	TSL:5	c.97-73704C>G		intron	N/A	ENSP00000489908.1	A0A1B0GU02

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152100

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

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:

1461884

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727244

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1112004

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152100

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74280

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.0000483

AC:

AN:

41408

American (AMR)

AF:

0.00

AC:

AN:

15268

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10594

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2092

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000203476), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

ClinVar

ClinVar submissions

Significance:Uncertain significance

Revision:criteria provided, single submitter

View on ClinVar

Pathogenic

VUS

Benign

Condition

Developmental and epileptic encephalopathy, 26 (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.058

BayesDel_addAF

Benign

-0.0029

BayesDel_noAF

Benign

-0.24

CADD

Benign

(source)

DANN

Benign

0.63

DEOGEN2

Benign

0.24

Eigen

Benign

-0.072

Eigen_PC

Benign

0.12

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Benign

0.62

M_CAP

Benign

0.029

MetaRNN

Benign

0.14

MetaSVM

Uncertain

0.30

MutationAssessor

Benign

0.34

PhyloP100

6.4

PrimateAI

Benign

0.35

PROVEAN

Benign

-0.29

REVEL

Benign

0.25

Sift

Benign

0.25

Sift4G

Benign

0.54

Polyphen

0.0020

Vest4

0.057

MVP

0.47

MPC

0.19

ClinPred

0.55

GERP RS

4.6

Varity_R

0.097

gMVP

0.26

Mutation Taster

=82/18

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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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over