17-63951465-C-T
Variant summary
Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PP2
The NM_000334.4(SCN4A):c.2812G>A(p.Glu938Lys) 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 1,607,776 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. E938E) has been classified as Likely benign.
Frequency
Consequence
NM_000334.4 missense
Scores
Clinical Significance
Conservation
Publications
- hyperkalemic periodic paralysisInheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P, Orphanet
- paramyotonia congenita of Von EulenburgInheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Laboratory for Molecular Medicine, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P, Orphanet
- SCN4A-related myopathy, autosomal recessiveInheritance: AR Classification: DEFINITIVE Submitted by: Illumina, ClinGen
- hypokalemic periodic paralysis, type 2Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
- potassium-aggravated myotoniaInheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
- congenital myasthenic syndrome 16Inheritance: AR Classification: STRONG, LIMITED Submitted by: PanelApp Australia, Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
- congenital myopathyInheritance: AR Classification: STRONG Submitted by: Genomics England PanelApp
- congenital myopathy 22A, classicInheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
- acetazolamide-responsive myotoniaInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- hypokalemic periodic paralysisInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- myotonia fluctuansInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- myotonia permanensInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- postsynaptic congenital myasthenic syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Uncertain_significance. The variant received 1 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes  0.0000131  AC: 2AN: 152106Hom.:  0  Cov.: 32 show subpopulations 
GnomAD2 exomes  AF:  0.00000402  AC: 1AN: 248590 AF XY:  0.00   show subpopulations 
GnomAD4 exome  AF:  0.0000124  AC: 18AN: 1455670Hom.:  0  Cov.: 32 AF XY:  0.0000111  AC XY: 8AN XY: 722716 show subpopulations 
Age Distribution
GnomAD4 genome  0.0000131  AC: 2AN: 152106Hom.:  0  Cov.: 32 AF XY:  0.0000135  AC XY: 1AN XY: 74306 show subpopulations 
ClinVar
Submissions by phenotype
not specified    Uncertain:1 
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Paramyotonia congenita of Von Eulenburg;C0238357:Familial hyperkalemic periodic paralysis;C2750061:Hypokalemic periodic paralysis, type 2;C2931826:Potassium-aggravated myotonia;C3280112:Congenital myasthenic syndrome 16;C5830453:Congenital myopathy 22A, classic;C5830501:Congenital myopathy 22B, severe fetal    Uncertain:1 
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not provided    Uncertain:1 
Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -
Familial hyperkalemic periodic paralysis    Uncertain:1 
This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 938 of the SCN4A protein (p.Glu938Lys). This variant is present in population databases (rs374673348, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with SCN4A-related conditions. ClinVar contains an entry for this variant (Variation ID: 448267). 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 SCN4A protein function with a negative predictive value of 95%. 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. -
Computational scores
Source: 
Splicing
 Find out detailed SpliceAI scores and Pangolin per-transcript scores at