rs1021551048

Positions:

• chr11-17779576-G-A
• chr11-17779576-G-C
• chr11-17779576-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_001112741.2(KCNC1):​c.1625G>A​(p.Arg542Lys) variant causes a missense change. The variant allele was found at a frequency of 0.00000286 in 1,399,248 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 (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000029 (0 hom.)
• Consequence: KCNC1 NM_001112741.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.57

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 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), KCNC1. . Gene score misZ 4.5189 (greater than the threshold 3.09). Trascript score misZ 5.1707 (greater than threshold 3.09). GenCC has associacion of gene with progressive myoclonic epilepsy type 7, progressive myoclonus epilepsy, complex neurodevelopmental disorder.
• BP4: Computational evidence support a benign effect (MetaRNN=0.24014214).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNC1	NM_001112741.2	c.1625G>A	p.Arg542Lys	missense_variant	3/4	ENST00000265969.8	NP_001106212.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNC1	ENST00000265969.8	c.1625G>A	p.Arg542Lys	missense_variant	3/4	5	NM_001112741.2	ENSP00000265969	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000286 AC: 4 AN: 1399248 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 690164

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000690

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

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

Labcorp Genetics (formerly Invitae), Labcorp

Oct 16, 2023

This sequence change replaces arginine, which is basic and polar, with lysine, which is basic and polar, at codon 542 of the KCNC1 protein (p.Arg542Lys). 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. ClinVar contains an entry for this variant (Variation ID: 567570). 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) performed at Invitae indicates that this missense variant is not expected to disrupt 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
BayesDel_addAF	Uncertain	0.11	D
BayesDel_noAF	Uncertain	-0.080
CADD	Benign	23
DANN	Uncertain	0.99
Eigen	Uncertain	0.38
Eigen_PC	Uncertain	0.48
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Benign	0.83	T
M_CAP	Benign	0.040	D
MetaRNN	Benign	0.24	T
MetaSVM	Uncertain	0.71	D
MutationTaster	Benign	0.68	N
PrimateAI	Uncertain	0.79	T
PROVEAN	Benign	-0.56	N
REVEL	Uncertain	0.36
Sift	Benign	0.25	T
Sift4G	Benign	0.43	T
Vest4		0.24
MutPred		0.33		Gain of methylation at R542 (P = 0.0062);
MVP		0.69
MPC		1.5
ClinPred		0.58	D
GERP RS		5.7
gMVP		0.53

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

Other links and lift over

dbSNP: rs1021551048; hg19: chr11-17801123;