10-76885982-A-G

Variant names:

• chr10-76885982-A-G
• rs200045921
• NM_001161352.2:c.*1284T>C

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_Strong BS1_Supporting

The NM_001161352.2(KCNMA1):​c.*1284T>C variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00124 in 985,376 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: 𝑓 0.00062 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0013 (0 hom.)
• Consequence: KCNMA1 NM_001161352.2 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.0990
• Publications: 0 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: Likely_benign. The variant received -5 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.92).
• BS1: Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.000624 (95/152246) while in subpopulation NFE AF = 0.00107 (73/68042). AF 95% confidence interval is 0.000875. There are 0 homozygotes in GnomAd4. There are 37 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNMA1	NM_001161352.2	c.*1284T>C		3_prime_UTR_variant	Exon 28 of 28	ENST00000286628.14	NP_001154824.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNMA1	ENST00000286628.14	c.*1284T>C		3_prime_UTR_variant	Exon 28 of 28	1	NM_001161352.2	ENSP00000286628.8

Frequencies

GnomAD3 genomes AF: 0.000624 AC: 95 AN: 152246 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000217

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000720

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: 0.00107

Gnomad OTH AF: 0.000955

GnomAD4 exome AF: 0.00135 AC: 1124 AN: 833130 Hom.: 0 Cov.: 32 AF XY: 0.00141 AC XY: 542 AN XY: 384728

African (AFR) AF: 0.000127 AC: 2 AN: 15786

American (AMR) AF: 0.00102 AC: 1 AN: 984

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 5152

East Asian (EAS) AF: 0.00 AC: 0 AN: 3632

South Asian (SAS) AF: 0.00 AC: 0 AN: 16460

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 276

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 1620

European-Non Finnish (NFE) AF: 0.00142 AC: 1080 AN: 761912

Other (OTH) AF: 0.00150 AC: 41 AN: 27308

GnomAD4 genome AF: 0.000624 AC: 95 AN: 152246 Hom.: 0 Cov.: 32 AF XY: 0.000497 AC XY: 37 AN XY: 74382

African (AFR) AF: 0.000217 AC: 9 AN: 41466

American (AMR) AF: 0.000720 AC: 11 AN: 15284

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4836

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10626

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00107 AC: 73 AN: 68042

Other (OTH) AF: 0.000955 AC: 2 AN: 2094

Alfa AF: 0.000529 Hom.: 0

Bravo AF: 0.000752

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Generalized epilepsy-paroxysmal dyskinesia syndrome Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.92
CADD	Benign	1.1
DANN	Benign	0.37
PhyloP100		-0.099

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: rs200045921; hg19: chr10-78645740;