rs1554829003

Variant names:

• chr10-77110181-C-T
• rs1554829003
• NM_001161352.2:c.1123G>A

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM2 PP3_Moderate PP5_Very_Strong

The NM_001161352.2(KCNMA1):​c.1123G>A​(p.Gly375Arg) variant causes a missense change involving the alteration of a conserved nucleotide. 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G375W) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNMA1 NM_001161352.2 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 7.90
• Publications: 1 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 Gene-Disease associations (from GenCC):

• generalized epilepsy-paroxysmal dyskinesia syndrome

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Illumina, G2P, Ambry Genetics, Orphanet, Labcorp Genetics (formerly Invitae), ClinGen
• Liang-Wang syndrome

  Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics
• cerebellar atrophy, developmental delay, and seizures

  Inheritance: AR Classification: STRONG, MODERATE Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.939
• PP5: Variant 10-77110181-C-T is Pathogenic according to our data. Variant chr10-77110181-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 521128.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNMA1	NM_001161352.2	c.1123G>A	p.Gly375Arg	missense_variant	Exon 8 of 28	ENST00000286628.14	NP_001154824.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNMA1	ENST00000286628.14	c.1123G>A	p.Gly375Arg	missense_variant	Exon 8 of 28	1	NM_001161352.2	ENSP00000286628.8

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Liang-Wang syndrome Pathogenic:2

Jan 10, 2020

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Nov 16, 2020

Centre of Medical Genetics, University of Antwerp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: curation

- -

Inborn genetic diseases Pathogenic:1

Nov 11, 2024

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1123G>A (p.G375R) alteration is located in exon 8 (coding exon 8) of the KCNMA1 gene. This alteration results from a G to A substitution at nucleotide position 1123, causing the glycine (G) at amino acid position 375 to be replaced by an arginine (R). for autosomal dominant KCNMA1-related neurological disorder; however, its clinical significance for autosomal recessive KCNMA1-related neurodevelopmental disorder is uncertain. This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This variant has been determined to be the result of a de novo mutation in multiple individuals with features consistent with KCNMA1-related neurodevelopmental movement disorder (Liang, 2019; Rodrigues Bento, 2021; Mameli, 2021; DECIPHER). This amino acid position is highly conserved in available vertebrate species. This missense alteration is located in a region that has a low rate of benign missense variation (Lek, 2016; Firth, 2009). This alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as pathogenic. -

not provided Pathogenic:1

Feb 12, 2021

Revvity Omics, Revvity

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.52
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.84	D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.
Eigen	Uncertain	0.56
Eigen_PC	Uncertain	0.61
FATHMM_MKL	Pathogenic	0.99	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;D
M_CAP	Pathogenic	0.57	D
MetaRNN	Pathogenic	0.94	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;D;D
MetaSVM	Uncertain	-0.18	T
MutationAssessor	Uncertain	2.2	.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;M;M;M;.;.;.;.;.;M;.;.;.;M;M;M;.;.;.
PhyloP100		7.9
PrimateAI	Pathogenic	0.93	D
PROVEAN	Pathogenic	-4.6	.;.;.;.;.;.;.;.;D;.;.;.;.;.;.;.;.;.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
REVEL	Pathogenic	0.97
Sift	Uncertain	0.016	.;.;.;.;.;.;.;.;D;.;.;.;.;.;.;.;.;.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
Sift4G	Uncertain	0.027	D;.;.;.;.;.;.;.;D;.;.;.;.;.;.;.;D;.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;D;D;D;.;.;.;.;.;.;.;D;.;.;.;.;.
Polyphen		1.0	.;.;.;.;.;.;.;.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;D;D;.;.;.;.;.;D;D;.;.;D;.;.;.;.;.
Vest4		0.89, 0.93, 0.89, 0.89, 0.94, 0.88, 0.83
MutPred		0.79		.;Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);.;Gain of methylation at G375 (P = 0.0053);.;Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);.;.;Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);.;.;.;.;.;.;Gain of methylation at G375 (P = 0.0053);.;Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);.;.;.;Gain of methylation at G375 (P = 0.0053);.;Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);.;Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);Gain of methylation at G375 (P = 0.0053);.;.;Gain of methylation at G375 (P = 0.0053);
MVP		0.98
MPC		2.5
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.93
gMVP		0.99
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs1554829003; hg19: chr10-78869939; COSMIC: COSV99695945;