Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM2PP3PP5_Very_Strong
The NM_001161352.2(KCNMA1):c.3158A>G(p.Asn1053Ser) 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 Pathogenic (★★).
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]
Our verdict: Pathogenic. The variant received 11 ACMG points.
PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.804
PP5
Variant 10-76891709-T-C is Pathogenic according to our data. Variant chr10-76891709-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 265313.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
This sequence change replaces asparagine, which is neutral and polar, with serine, which is neutral and polar, at codon 995 of the KCNMA1 protein (p.Asn995Ser). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with autosomal dominant epilepsy and/or paroxysomal dyskinesia (PMID: 26195193, 29330545; Invitae). In at least one individual the variant was observed to be de novo. This variant is also known as c.3158A>G (p.Asn1053Ser). ClinVar contains an entry for this variant (Variation ID: 265313). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on KCNMA1 protein function. Experimental studies have shown that this missense change affects KCNMA1 function (PMID: 29330545). For these reasons, this variant has been classified as Pathogenic. -
Oct 05, 2018
Undiagnosed Diseases Network, NIH
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing
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Sep 08, 2002
Center of Excellence for Medical Genomics, Chulalongkorn University
Significance:Likely pathogenic
Review Status:no assertion criteria provided
Collection Method:research
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not providedPathogenic:2
Jan 03, 2023
GeneDx
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing
Published functional studies demonstrate that N995S results in a gain-of-function with markedly increased macroscopic potassium current (Li et al., 2018; Moldenhauer et al., 2020); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); Also known as N1053S using alternate nomenclature; This variant is associated with the following publications: (PMID: 32132200, 32655623, 26195193, 29330545, 30525188, 31152168, 31851553, 32633875, 33043086, 33767182) -