rs751919609

Variant names:

• chr10-76969984-T-C
• rs751919609
• NM_001161352.2:c.2350A>G

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_001161352.2(KCNMA1):​c.2350A>G​(p.Lys784Glu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,038 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 30)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: KCNMA1 NM_001161352.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.66
• Publications: 2 publications found

Genes affected

KCNMA1 (HGNC:6284): (potassium calcium-activated channel subfamily M alpha 1) This gene encodes the alpha subunit of calcium-activated BK channel. The encoded protein is involved in several physiological processes including smooth muscle contraction, neurotransmitter release and neuronal excitability. Mutations in this gene are associated with a spectrum of neurological disorders including Paroxysmal Nonkinesigenic Dyskinesia 3, Idiopathic Generalized Epilepsy 16 and Liang-Wang syndrome. [provided by RefSeq, Aug 2022]

KCNMA1-AS1 (HGNC:51213): (KCNMA1 antisense RNA 1)

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNMA1	NM_001161352.2	c.2350A>G	p.Lys784Glu	missense_variant	Exon 20 of 28	ENST00000286628.14	NP_001154824.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNMA1	ENST00000286628.14	c.2350A>G	p.Lys784Glu	missense_variant	Exon 20 of 28	1	NM_001161352.2	ENSP00000286628.8

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD2 exomes AF: 0.00000795 AC: 2 AN: 251436 AF XY: 0.00000736

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461038 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726884

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

African (AFR) AF: 0.00 AC: 0 AN: 33456

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39686

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86242

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5758

European-Non Finnish (NFE) AF: 0.00000360 AC: 4 AN: 1111250

Other (OTH) AF: 0.00 AC: 0 AN: 60370

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0000455559), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 30

ExAC AF: 0.0000165 AC: 2

EpiCase AF: 0.00

EpiControl AF: 0.000119

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Generalized epilepsy-paroxysmal dyskinesia syndrome Uncertain:1

Sep 07, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with KCNMA1-related disease. This variant is present in population databases (rs751919609, ExAC 0.003%). This sequence change replaces lysine with glutamic acid at codon 726 of the KCNMA1 protein (p.Lys726Glu). The lysine residue is moderately conserved and there is a small physicochemical difference between lysine and glutamic acid. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.35
BayesDel_addAF	Pathogenic	0.21	D
BayesDel_noAF	Uncertain	0.080
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.019	T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;T;.;.;.;.;.;.;.;.;.;.;.;.;.
Eigen	Uncertain	0.19
Eigen_PC	Uncertain	0.34
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Pathogenic	0.98	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;.;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Benign	0.061	D
MetaRNN	Uncertain	0.46	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	-0.020	T
MutationAssessor	Benign	1.2	.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;L;.;.;.;.;.;.;.;.;.;.;.;.;.;.
PhyloP100		7.7
PrimateAI	Uncertain	0.69	T
PROVEAN	Benign	-1.2	.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;N;.;.;.;.;.;.;.;.;N;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
REVEL	Uncertain	0.48
Sift	Benign	0.21	.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;.;.;.;.;.;.;.;.;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
Sift4G	Benign	0.29	T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;T;T;T;.;.;.;.;.;.;.;.;T;.;.;.
Polyphen		0.61, 0.0080, 0.16, 0.0, 0.77	.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;P;B;B;.;.;.;.;.;.;P;B;.;.;P;.;.;.
Vest4		0.77, 0.75, 0.78, 0.72, 0.52, 0.70
MutPred		0.41		.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;Loss of methylation at K784 (P = 0.0034);Loss of methylation at K784 (P = 0.0034);.;.;.;.;.;.;.;.;.;.;.;.;.;.;Loss of methylation at K784 (P = 0.0034);.;.;.;Loss of methylation at K784 (P = 0.0034);.;.;.;.;.;.;.;.;.;.;.;.;.;.;
MVP		0.95
MPC		1.8
ClinPred		0.63	D
GERP RS		5.7
Varity_R		0.72
gMVP		0.79
Mutation Taster		=57/43	polymorphism

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

Other links and lift over

dbSNP: rs751919609; hg19: chr10-78729742;