Genetic Variant KCNAB2:p.Arg38Trp (chr1-6051648-C-T) – ACMG Classification: Likely_benign (-5 pts)

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4BS2

The NM_001199862.2(KCNAB2):c.112C>T(p.Arg38Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000143 in 1,534,062 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. R38Q) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000012 ( 0 hom. )

Consequence

KCNAB2
NM_001199862.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 2.75

Variant links:

Genes affected

KCNAB2 (HGNC:6229): (potassium voltage-gated channel subfamily A regulatory beta subunit 2) 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, shaker-related subfamily. This member is one of the beta subunits, which are auxiliary proteins associating with functional Kv-alpha subunits. This member alters functional properties of the KCNA4 gene product. Alternative splicing of this gene results in multiple transcript variants encoding distinct isoforms. [provided by RefSeq, Dec 2010]

KCNAB2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -5 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.37620658).

BS2

High AC in GnomAd4 at 5 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNAB2	NM_001199862.2 link	c.112C>T	p.Arg38Trp	missense_variant	Exon 2 of 16	ENST00000378083.8	NP_001186791.1	Q13303-3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNAB2	ENST00000378083.8 link	c.112C>T	p.Arg38Trp	missense_variant	Exon 2 of 16	2	NM_001199862.2	ENSP00000367323.3		Q13303-3

Frequencies

GnomAD3 genomes

AF:

0.0000328

AC:

AN:

152226

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000757

AC:

AN:

132106

Hom.:

AF XY:

0.00

AC XY:

AN XY:

72074

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000197

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000123

AC:

AN:

1381836

Hom.:

Cov.:

AF XY:

0.0000176

AC XY:

AN XY:

681878

show subpopulations

Gnomad4 AFR exome

AF:

0.0000317

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000560

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000121

Gnomad4 OTH exome

AF:

0.0000173

GnomAD4 genome

AF:

0.0000328

AC:

AN:

152226

Hom.:

Cov.:

AF XY:

0.0000672

AC XY:

AN XY:

74384

show subpopulations

Gnomad4 AFR

AF:

0.0000724

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000416

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Dec 21, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.112C>T (p.R38W) alteration is located in exon 2 (coding exon 1) of the KCNAB2 gene. This alteration results from a C to T substitution at nucleotide position 112, causing the arginine (R) at amino acid position 38 to be replaced by a tryptophan (W). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Benign

-0.12

BayesDel_noAF

Benign

-0.41

CADD

Pathogenic

DANN

Pathogenic

1.0

Eigen

Uncertain

0.35

Eigen_PC

Uncertain

0.35

FATHMM_MKL

Benign

0.74

LIST_S2

Benign

0.82

M_CAP

Pathogenic

0.47

MetaRNN

Benign

0.38

MetaSVM

Benign

-1.1

PrimateAI

Uncertain

0.51

PROVEAN

Benign

-2.1

REVEL

Benign

0.13

Sift

Uncertain

0.0010

Sift4G

Uncertain

0.010

Polyphen

0.99

Vest4

0.32

MutPred

0.46

Loss of disorder (P = 8e-04);

MVP

0.093

MPC

2.0

ClinPred

0.93

GERP RS

4.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

2.9

gMVP

0.73

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over