rs775163829

Variant names:

• chr11-17771882-G-A
• rs775163829
• NM_001112741.2:c.788G>A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_001112741.2(KCNC1):​c.788G>A​(p.Arg263His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,880 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: KCNC1 NM_001112741.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 10.0

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 Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.983

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNC1	NM_001112741.2	c.788G>A	p.Arg263His	missense_variant	Exon 2 of 4	ENST00000265969.8	NP_001106212.1
KCNC1	NM_004976.4	c.788G>A	p.Arg263His	missense_variant	Exon 2 of 2		NP_004967.1
KCNC1	XM_047426916.1	c.788G>A	p.Arg263His	missense_variant	Exon 2 of 4		XP_047282872.1
KCNC1	XR_930866.3	n.2010G>A		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	c.788G>A	p.Arg263His	missense_variant	Exon 2 of 4	5	NM_001112741.2	ENSP00000265969.7

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251486 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135916

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: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461880 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727238

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Progressive myoclonic epilepsy type 7 Uncertain:1

Jul 05, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is present in population databases (rs775163829, ExAC 0.001%). This sequence change replaces arginine with histidine at codon 263 of the KCNC1 protein (p.Arg263His). The arginine residue is highly conserved and there is a small physicochemical difference between arginine and histidine. This variant has not been reported in the literature in individuals with KCNC1-related disease. 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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.94	D;.
Eigen	Pathogenic	0.87
Eigen_PC	Pathogenic	0.80
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Pathogenic	0.52	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.0	M;M
PrimateAI	Pathogenic	0.83	D
PROVEAN	Pathogenic	-4.7	D;D
REVEL	Pathogenic	0.93
Sift	Uncertain	0.016	D;D
Sift4G	Uncertain	0.012	D;D
Polyphen		1.0	D;.
Vest4		0.88
MutPred		0.88		Gain of catalytic residue at V264 (P = 0.212);Gain of catalytic residue at V264 (P = 0.212);
MVP		0.98
MPC		3.0
ClinPred		1.0	D
GERP RS		4.8
Varity_R		0.61
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

LitVar

Other links and lift over

dbSNP: rs775163829; hg19: chr11-17793429; COSMIC: COSV56391072; COSMIC: COSV56391072;