rs758964585

Variant names:

• chr20-49373036-G-A
• rs758964585
• NM_004975.4:c.2524C>T

Variant summary

Our verdict is Benign. The variant received -13 ACMG points: 0P and 13B. BP4 BP6_Very_Strong BS2

The NM_004975.4(KCNB1):​c.2524C>T​(p.Arg842Cys) variant causes a missense change. The variant allele was found at a frequency of 0.000018 in 1,613,848 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 Likely benign (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R842H) has been classified as Benign.

• Frequency:
  • Genomes: 𝑓 0.000033 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000016 (0 hom.)
• Consequence: KCNB1 NM_004975.4 missense
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:2
• Conservation: PhyloP100: 6.42
• Publications: 0 publications found

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

ENSG00000290421 (HGNC:):

ACMG classification

Our verdict: Benign. The variant received -13 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.34654224).
• BP6: Variant 20-49373036-G-A is Benign according to our data. Variant chr20-49373036-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 998443.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS2: High AC in GnomAd4 at 5 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNB1	NM_004975.4	c.2524C>T	p.Arg842Cys	missense_variant	Exon 2 of 2	ENST00000371741.6	NP_004966.1
KCNB1	XM_011528799.3	c.2524C>T	p.Arg842Cys	missense_variant	Exon 3 of 3		XP_011527101.1
LOC105372649	XR_001754659.2	n.1201+41012G>A		intron_variant	Intron 2 of 3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNB1	ENST00000371741.6	c.2524C>T	p.Arg842Cys	missense_variant	Exon 2 of 2	1	NM_004975.4	ENSP00000360806.3

Frequencies

GnomAD3 genomes AF: 0.0000329 AC: 5 AN: 152088 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000386

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000279 AC: 7 AN: 251136 AF XY: 0.0000368

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000545

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000528

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000164 AC: 24 AN: 1461760 Hom.: 0 Cov.: 32 AF XY: 0.0000179 AC XY: 13 AN XY: 727186

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44698

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.000227 AC: 9 AN: 39696

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86226

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5752

European-Non Finnish (NFE) AF: 0.0000117 AC: 13 AN: 1111974

Other (OTH) AF: 0.0000166 AC: 1 AN: 60390

GnomAD4 genome AF: 0.0000329 AC: 5 AN: 152088 Hom.: 0 Cov.: 32 AF XY: 0.0000404 AC XY: 3 AN XY: 74280

African (AFR) AF: 0.00 AC: 0 AN: 41398

American (AMR) AF: 0.00 AC: 0 AN: 15284

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.000386 AC: 2 AN: 5188

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10590

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000441 AC: 3 AN: 68016

Other (OTH) AF: 0.00 AC: 0 AN: 2086

Alfa AF: 0.0000564 Hom.: 0

Bravo AF: 0.00000378

ExAC AF: 0.0000165 AC: 2

EpiCase AF: 0.0000545

EpiControl AF: 0.0000593

ClinVar

Significance: Likely benign

Submissions summary: Benign:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Developmental and epileptic encephalopathy, 26 Benign:1

Jul 23, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Inborn genetic diseases Benign:1

Sep 29, 2023

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.089
BayesDel_addAF	Benign	-0.025	T
BayesDel_noAF	Benign	-0.11
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.35	T;T
Eigen	Uncertain	0.28
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.91	.;D
M_CAP	Uncertain	0.18	D
MetaRNN	Benign	0.35	T;T
MetaSVM	Uncertain	0.46	D
MutationAssessor	Benign	0.55	N;N
PhyloP100		6.4
PrimateAI	Benign	0.32	T
PROVEAN	Benign	-1.4	N;.
REVEL	Uncertain	0.43
Sift	Uncertain	0.0020	D;.
Sift4G	Uncertain	0.011	D;D
Polyphen		0.95	P;P
Vest4		0.14
MutPred		0.62		Loss of disorder (P = 0.0349);Loss of disorder (P = 0.0349);
MVP		0.38
MPC		0.29
ClinPred		0.46	T
GERP RS		4.6
Varity_R		0.13
gMVP		0.53
Mutation Taster		=90/10	polymorphism

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

Other links and lift over

dbSNP: rs758964585; hg19: chr20-47989573; COSMIC: COSV108208017; COSMIC: COSV108208017;