Genetic Variant KCNB1:p.Lys59Lys (chr20-49482304-C-T) – ACMG Classification: Benign (-17 pts)

Variant summary

Our verdict is Benign. The variant received -17 ACMG points: 0P and 17B. BP4_StrongBP6_Very_StrongBP7BS2

The NM_004975.4(KCNB1):c.177G>A(p.Lys59Lys) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000349 in 1,609,492 control chromosomes in the GnomAD database, including 8 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.00049 ( 2 hom., cov: 32)

Exomes 𝑓: 0.00033 ( 6 hom. )

Consequence

KCNB1
NM_004975.4 synonymous

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:3

Conservation

PhyloP100: 0.167

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:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -17 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.49).

BP6

Variant 20-49482304-C-T is Benign according to our data. Variant chr20-49482304-C-T is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 383991.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=0.167 with no splicing effect.

BS2

High AC in GnomAd4 at 75 AD gene.

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.177G>A	p.Lys59Lys	synonymous	Exon 1 of 2	NP_004966.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNB1	ENST00000371741.6	TSL:1 MANE Select	c.177G>A	p.Lys59Lys	synonymous	Exon 1 of 2	ENSP00000360806.3
	KCNB1	ENST00000635465.1	TSL:1	c.177G>A	p.Lys59Lys	synonymous	Exon 2 of 3	ENSP00000489193.1

Frequencies

GnomAD3 genomes

AF:

0.000486

AC:

AN:

152236

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000482

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000196

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.0129

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.000478

GnomAD2 exomes

AF:

0.00110

AC:

265

AN:

241926

AF XY:

0.00104

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000585

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0143

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000848

GnomAD4 exome

AF:

0.000334

AC:

486

AN:

1457138

Hom.:

Cov.:

AF XY:

0.000329

AC XY:

238

AN XY:

724318

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33402

American (AMR)

AF:

0.0000673

AC:

AN:

44564

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26046

East Asian (EAS)

AF:

0.0110

AC:

437

AN:

39562

South Asian (SAS)

AF:

0.0000349

AC:

AN:

85992

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52068

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5718

European-Non Finnish (NFE)

AF:

0.00000360

AC:

AN:

1109662

Other (OTH)

AF:

0.000649

AC:

AN:

60124

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.501

Heterozygous variant carriers

105

140

175

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

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:

0.000492

AC:

AN:

152354

Hom.:

Cov.:

AF XY:

0.000483

AC XY:

AN XY:

74510

show subpopulations

African (AFR)

AF:

0.0000481

AC:

AN:

41584

American (AMR)

AF:

0.000196

AC:

AN:

15312

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.0129

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68022

Other (OTH)

AF:

0.000945

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.480

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Genome Hom

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:

0.000101

Hom.:

Bravo

AF:

0.000536

Asia WGS

AF:

0.00260

AC:

AN:

3478

ClinVar

ClinVar submissions as Germline

Significance:Benign/Likely benign

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

Developmental and epileptic encephalopathy, 26 (1)

not provided (1)

not specified (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.49

CADD

Benign

(source)

DANN

Benign

0.64

PhyloP100

0.17

PromoterAI

-0.0078

Neutral

(source)

Mutation Taster

=100/0

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