NM_001112741.2:c.692C>T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM2PM5PP3

The NM_001112741.2(KCNC1):c.692C>T(p.Thr231Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,888 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. T231A) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

KCNC1
NM_001112741.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 7.91

Publications

0 publications found

Variant links:

Genes affected

KCNC1 (HGNC:6233): (potassium voltage-gated channel subfamily C member 1) This gene encodes a member of a family of integral membrane proteins that mediate the voltage-dependent potassium ion permeability of excitable membranes. Alternative splicing is thought to result in two transcript variants encoding isoforms that differ at their C-termini. These isoforms have had conflicting names in the literature: the longer isoform has been called both "b" and "alpha", while the shorter isoform has been called both "a" and "beta" (PMIDs 1432046, 12091563). [provided by RefSeq, Oct 2014]

KCNC1 Gene-Disease associations (from GenCC):

complex neurodevelopmental disorder
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen, Ambry Genetics
progressive myoclonic epilepsy type 7
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet, G2P
progressive myoclonus epilepsy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen

KCNC1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr11-17771785-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 568146.Status of the report is criteria_provided_single_submitter, 1 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.78

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNC1	NM_001112741.2 link	c.692C>T	p.Thr231Met	missense_variant	Exon 2 of 4	ENST00000265969.8	NP_001106212.1	P48547-2
KCNC1	NM_004976.4 link	c.692C>T	p.Thr231Met	missense_variant	Exon 2 of 2		NP_004967.1	P48547-1
KCNC1	XM_047426916.1 link	c.692C>T	p.Thr231Met	missense_variant	Exon 2 of 4		XP_047282872.1
KCNC1	XR_930866.3 link	n.1914C>T		non_coding_transcript_exon_variant	Exon 2 of 3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNC1	ENST00000265969.8 link	c.692C>T	p.Thr231Met	missense_variant	Exon 2 of 4	5	NM_001112741.2	ENSP00000265969.7		P48547-2

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152246

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000205

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:

0.00

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:

0.00000270

AC:

AN:

1112006

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.442

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.00000656

AC:

AN:

152364

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74510

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

41594

American (AMR)

AF:

0.00

AC:

AN:

15312

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3466

East Asian (EAS)

AF:

0.00

AC:

AN:

5180

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10630

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68030

Other (OTH)

AF:

0.00

AC:

AN:

2116

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.225

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000439

Hom.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Progressive myoclonic epilepsy type 7

Uncertain:1

Dec 24, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces threonine with methionine at codon 231 of the KCNC1 protein (p.Thr231Met). The threonine residue is highly conserved and there is a moderate physicochemical difference between threonine and methionine. This variant is not present in population databases (ExAC no frequency). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. 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: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with KCNC1-related disease. -

not provided

Uncertain:1

Jan 13, 2022

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.35

BayesDel_addAF

Pathogenic

0.37

BayesDel_noAF

Pathogenic

0.29

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.86

D;.

Eigen

Pathogenic

0.70

Eigen_PC

Uncertain

0.66

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.84

T;T

M_CAP

Uncertain

0.24

MetaRNN

Pathogenic

0.78

D;D

MetaSVM

Uncertain

0.58

MutationAssessor

Pathogenic

3.3

M;M

PhyloP100

7.9

PrimateAI

Uncertain

0.79

PROVEAN

Uncertain

-3.3

D;D

REVEL

Pathogenic

0.74

Sift

Uncertain

0.0060

D;D

Sift4G

Uncertain

0.017

D;D

Polyphen

1.0

D;.

Vest4

0.53

MutPred

0.38

Loss of phosphorylation at T231 (P = 0.0365);Loss of phosphorylation at T231 (P = 0.0365);

MVP

0.92

MPC

2.6

ClinPred

0.99

GERP RS

4.7

PromoterAI

-0.036

Neutral

(source)

Varity_R

0.13

gMVP

0.84

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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NM_001112741.2:c.692C>T

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over