11-17736076-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_001112741.2(KCNC1):c.74C>T(p.Thr25Ile) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNC1 NM_001112741.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.07

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, KCNC1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.912

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNC1	NM_001112741.2	c.74C>T	p.Thr25Ile	missense_variant	1/4	ENST00000265969.8
KCNC1	NM_004976.4	c.74C>T	p.Thr25Ile	missense_variant	1/2
KCNC1	XM_047426916.1	c.74C>T	p.Thr25Ile	missense_variant	1/4
KCNC1	XR_930866.3	n.1296C>T		non_coding_transcript_exon_variant	1/3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNC1	ENST00000265969.8	c.74C>T	p.Thr25Ile	missense_variant	1/4	5	NM_001112741.2	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Progressive myoclonic epilepsy type 7 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 10, 2023

This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 25 of the KCNC1 protein (p.Thr25Ile). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with KCNC1-related conditions. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on KCNC1 protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.35
Cadd	Pathogenic	33
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.87	D;.
Eigen	Pathogenic	0.69
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Uncertain	0.97	D;D
M_CAP	Pathogenic	0.74	D
MetaRNN	Pathogenic	0.91	D;D
MetaSVM	Uncertain	0.64	D
MutationAssessor	Pathogenic	3.4	M;M
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.83	D
PROVEAN	Pathogenic	-4.6	D;D
REVEL	Pathogenic	0.91
Sift	Uncertain	0.0010	D;D
Sift4G	Uncertain	0.0020	D;D
Polyphen		1.0	D;.
Vest4		0.69
MutPred		0.73		Loss of disorder (P = 0.0306);Loss of disorder (P = 0.0306);
MVP		0.90
MPC		2.8
ClinPred		1.0	D
GERP RS		4.4
Varity_R		0.76
gMVP		0.99

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr11-17757623;