Our verdict is Uncertain significance. Variant got 0 ACMG points: 1P and 1B. PP2BP4
The NM_001161352.2(KCNMA1):c.2367C>A(p.Asp789Glu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000124 in 1,613,952 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 (★★).
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]
Verdict is Uncertain_significance. Variant got 0 ACMG points.
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=0.3501129).
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The c.2193C>A (p.D731E) alteration is located in exon 20 (coding exon 20) of the KCNMA1 gene. This alteration results from a C to A substitution at nucleotide position 2193, causing the aspartic acid (D) at amino acid position 731 to be replaced by a glutamic acid (E). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -
not provided Uncertain:1
Jan 15, 2014
Genetic Services Laboratory, University of Chicago
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This sequence change replaces aspartic acid, which is acidic and polar, with glutamic acid, which is acidic and polar, at codon 731 of the KCNMA1 protein (p.Asp731Glu). This variant is present in population databases (rs587780363, gnomAD 0.006%). This variant has not been reported in the literature in individuals affected with KCNMA1-related conditions. ClinVar contains an entry for this variant (Variation ID: 129322). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt KCNMA1 protein function with a negative predictive value of 80%. 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. -