Genetic Variant NM_004770.3:c.1374C>A (chr8-72936729-C-A) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2PP3_Moderate

The NM_004770.3(KCNB2):c.1374C>A(p.Phe458Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,870 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Synonymous variant affecting the same amino acid position (i.e. F458F) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

KCNB2
NM_004770.3 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 0.0960

Publications

0 publications found

Variant links:

Genes affected

KCNB2 (HGNC:6232): (potassium voltage-gated channel subfamily B member 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, shab-related subfamily. This member is a delayed rectifier potassium channel. The gene is expressed in gastrointestinal smooth muscle cells. [provided by RefSeq, Jul 2008]

KCNB2 Gene-Disease associations (from GenCC):

neurodevelopmental disorder
Inheritance: AD Classification: MODERATE Submitted by: Ambry Genetics

KCNB2 links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.862

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004770.3. 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
	KCNB2	NM_004770.3	MANE Select	c.1374C>A	p.Phe458Leu	missense	Exon 3 of 3	NP_004761.2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNB2	ENST00000523207.2	TSL:1 MANE Select	c.1374C>A	p.Phe458Leu	missense	Exon 3 of 3	ENSP00000430846.1	Q92953

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461870

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727242

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:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111998

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

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.99

BayesDel_addAF

Pathogenic

0.28

BayesDel_noAF

Pathogenic

0.17

CADD

Benign

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.40

Eigen

Benign

-0.17

Eigen_PC

Benign

-0.34

FATHMM_MKL

Uncertain

0.83

LIST_S2

Pathogenic

0.98

M_CAP

Pathogenic

0.58

MetaRNN

Pathogenic

0.86

MetaSVM

Pathogenic

0.87

MutationAssessor

Uncertain

2.2

PhyloP100

0.096

PrimateAI

Pathogenic

0.88

PROVEAN

Pathogenic

-5.4

REVEL

Pathogenic

0.67

Sift

Benign

0.045

Sift4G

Uncertain

0.010

Polyphen

1.0

Vest4

0.88

MutPred

0.40

Gain of ubiquitination at K455 (P = 0.0469)

MVP

0.93

MPC

1.5

ClinPred

1.0

GERP RS

-6.5

Varity_R

0.28

gMVP

0.91

Mutation Taster

=54/46

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

ClinVar

Computational scores

Splicing

Publications

Other links and lift over