10-76889472-G-T

Variant names:

• chr10-76889472-G-T
• rs1253143924
• NM_001161352.2:c.3440C>A

Variant summary

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

The NM_001161352.2(KCNMA1):​c.3440C>A​(p.Thr1147Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,459,544 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: 0.0000014 (0 hom.)
• Consequence: KCNMA1 NM_001161352.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.68

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

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the KCNMA1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 12 curated pathogenic missense variants (we use a threshold of 10). The gene has 25 curated benign missense variants. Gene score misZ: 5.0622 (above the threshold of 3.09). Trascript score misZ: 6.5162 (above the threshold of 3.09). GenCC associations: The gene is linked to cerebellar atrophy, developmental delay, and seizures, generalized epilepsy-paroxysmal dyskinesia syndrome, Liang-Wang syndrome.
• BP4: Computational evidence support a benign effect (MetaRNN=0.23965266).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNMA1	NM_001161352.2	c.3440C>A	p.Thr1147Asn	missense_variant	Exon 27 of 28	ENST00000286628.14	NP_001154824.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNMA1	ENST00000286628.14	c.3440C>A	p.Thr1147Asn	missense_variant	Exon 27 of 28	1	NM_001161352.2	ENSP00000286628.8

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251272 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135794

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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1459544 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 726278

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: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.01e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Generalized epilepsy-paroxysmal dyskinesia syndrome Uncertain:1

Mar 04, 2022

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. This variant has not been reported in the literature in individuals affected with KCNMA1-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.0009%). This sequence change replaces threonine, which is neutral and polar, with asparagine, which is neutral and polar, at codon 1089 of the KCNMA1 protein (p.Thr1089Asn). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Uncertain	0.052	T
BayesDel_noAF	Benign	-0.16
CADD	Uncertain	24
DANN	Benign	0.96
DEOGEN2	Benign	0.019	T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;T;.;.;.;.;.;.;.;.;.;.;.;.;.
Eigen	Benign	0.11
Eigen_PC	Uncertain	0.35
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	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	0.014	T
MetaRNN	Benign	0.24	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	Benign	-0.46	T
MutationAssessor	Benign	-0.42	.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;N;.;.;.;.;.;.;.;.;.;.;.;.;.;.
PrimateAI	Uncertain	0.76	T
PROVEAN	Uncertain	-4.0	.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;.;.;.;.;.;.;.;N;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
REVEL	Uncertain	0.29
Sift	Uncertain	0.0020	.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;.;.;.;.;.;.;.;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
Sift4G	Benign	0.71	T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;T;T;T;.;.;.;.;.;.;.;.;T;.;.;.
Polyphen		0.26, 0.0010, 0.0030	.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;B;B;B;.;.;.;.;.;.;B;B;.;.;B;.;.;.
Vest4		0.26, 0.29, 0.30, 0.28, 0.24, 0.30
MutPred		0.13		.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;Loss of glycosylation at T1147 (P = 0.0764);Loss of glycosylation at T1147 (P = 0.0764);.;.;.;.;.;.;.;.;.;.;.;.;.;.;Loss of glycosylation at T1147 (P = 0.0764);.;.;.;Loss of glycosylation at T1147 (P = 0.0764);.;.;.;.;.;.;.;.;.;.;.;.;.;.;
MVP		0.72
MPC		1.5
ClinPred		0.45	T
GERP RS		6.2
Varity_R		0.32
gMVP		0.78

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: rs1253143924; hg19: chr10-78649230;