10-77637505-AGAGGAGGAGGAG-AGAGGAGGAGGAGGAGGAGGAGGAG

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP3BP6

The NM_001161352.2(KCNMA1):c.126_137dupCTCCTCCTCCTC(p.Ser43_Ser46dup) variant causes a disruptive inframe insertion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000165 in 1,572,860 control chromosomes in the GnomAD database, with no homozygous occurrence. It is difficult to determine the true allele frequency of this variant because it is of type INS_BIG, and the frequency of such variant types in population databases may be underestimated and unreliable. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000017 ( 0 hom. )

Consequence

KCNMA1
NM_001161352.2 disruptive_inframe_insertion

Scores

Not classified

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:1

Conservation

PhyloP100: 2.55

Publications

2 publications found

Variant links:

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)

KCNMA1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

BP3

Nonframeshift variant in repetitive region in NM_001161352.2

BP6

Variant 10-77637505-A-AGAGGAGGAGGAG is Benign according to our data. Variant chr10-77637505-A-AGAGGAGGAGGAG is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1345098.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNMA1	NM_001161352.2 link	c.126_137dupCTCCTCCTCCTC	p.Ser43_Ser46dup	disruptive_inframe_insertion	Exon 1 of 28	ENST00000286628.14	NP_001154824.1	Q12791-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNMA1	ENST00000286628.14 link	c.126_137dupCTCCTCCTCCTC	p.Ser43_Ser46dup	disruptive_inframe_insertion	Exon 1 of 28	1	NM_001161352.2	ENSP00000286628.8		Q12791-1

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

151442

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000295

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000521

AC:

AN:

191788

AF XY:

0.00000967

show subpopulations

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:

0.0000122

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000169

AC:

AN:

1421418

Hom.:

Cov.:

AF XY:

0.0000156

AC XY:

AN XY:

705782

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

32584

American (AMR)

AF:

0.0000240

AC:

AN:

41604

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25564

East Asian (EAS)

AF:

0.0000262

AC:

AN:

38230

South Asian (SAS)

AF:

0.0000121

AC:

AN:

82954

European-Finnish (FIN)

AF:

0.00

AC:

AN:

51258

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5716

European-Non Finnish (NFE)

AF:

0.0000175

AC:

AN:

1084594

Other (OTH)

AF:

0.0000339

AC:

AN:

58914

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.408

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000132

AC:

AN:

151442

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

73946

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

41238

American (AMR)

AF:

0.00

AC:

AN:

15228

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3464

East Asian (EAS)

AF:

0.00

AC:

AN:

5098

South Asian (SAS)

AF:

0.00

AC:

AN:

4798

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10512

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.0000295

AC:

AN:

67808

Other (OTH)

AF:

0.00

AC:

AN:

2072

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.00233887), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.350

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Generalized epilepsy-paroxysmal dyskinesia syndrome

Uncertain:1

May 28, 2023

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. Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. This variant has not been reported in the literature in individuals affected with KCNMA1-related conditions. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant, c.126_137dup, results in the insertion of 4 amino acid(s) of the KCNMA1 protein (p.Ser57_Ser60dup), but otherwise preserves the integrity of the reading frame. -

Inborn genetic diseases

Benign:1

May 05, 2022

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

2.6

Mutation Taster

=79/21

polymorphism

(source)

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over