20-49373360-G-A

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.2200C>T(p.Pro734Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,613,928 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P734L) has been classified as Likely benign.

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: 7.42

Publications

1 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 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.25944436).

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNB1	NM_004975.4	MANE Select	c.2200C>T	p.Pro734Ser	missense	Exon 2 of 2	NP_004966.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
KCNB1	ENST00000371741.6	TSL:1 MANE Select	c.2200C>T	p.Pro734Ser	missense	Exon 2 of 2	ENSP00000360806.3
KCNB1	ENST00000635465.1	TSL:1	c.2200C>T	p.Pro734Ser	missense	Exon 3 of 3	ENSP00000489193.1
KCNB1	ENST00000635878.1	TSL:5	c.97-73977C>T		intron	N/A	ENSP00000489908.1

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152040

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

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:

1461888

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727246

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

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:

1112006

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:

0.00000658

AC:

AN:

152040

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74276

show subpopulations

African (AFR)

AF:

0.0000242

AC:

AN:

41384

American (AMR)

AF:

0.00

AC:

AN:

15270

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5172

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10600

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68002

Other (OTH)

AF:

0.00

AC:

AN:

2090

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

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

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Developmental and epileptic encephalopathy, 26

Uncertain:1

May 26, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with a KCNB1-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C25"). In summary, this variant has uncertain impact on KCNB1 function. The available evidence is currently insufficient to determine its role in disease. Therefore, it has been classified as a Variant of Uncertain Significance. This sequence change replaces proline with serine at codon 734 of the KCNB1 protein (p.Pro734Ser). The proline residue is highly conserved and there is a moderate physicochemical difference between proline and serine.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.13

BayesDel_addAF

Uncertain

0.14

BayesDel_noAF

Uncertain

-0.040

CADD

Benign

(source)

DANN

Benign

0.84

DEOGEN2

Benign

0.29

Eigen

Benign

0.13

Eigen_PC

Uncertain

0.23

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.82

M_CAP

Uncertain

0.094

MetaRNN

Benign

0.26

MetaSVM

Uncertain

0.42

MutationAssessor

Benign

1.7

PhyloP100

7.4

PrimateAI

Uncertain

0.55

PROVEAN

Benign

-0.98

REVEL

Uncertain

0.40

Sift

Benign

0.74

Sift4G

Benign

0.68

Polyphen

0.63

Vest4

0.24

MutPred

0.27

Loss of catalytic residue at P734 (P = 0.0047)

MVP

0.53

MPC

0.34

ClinPred

0.40

GERP RS

4.2

Varity_R

0.088

gMVP

0.56

Mutation Taster

=47/53

disease causing

(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

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over