chr17-63948753-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.3002G>A(p.Arg1001His) variant causes a missense change. The variant allele was found at a frequency of 0.0000236 in 1,607,852 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1001C) 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
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| SCN4A | NM_000334.4 | c.3002G>A | p.Arg1001His | missense_variant | Exon 16 of 24 | ENST00000435607.3 | NP_000325.4 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152210Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000204 AC: 5AN: 244522 AF XY: 0.0000301 show subpopulations
GnomAD4 exome AF: 0.0000247 AC: 36AN: 1455642Hom.: 0 Cov.: 31 AF XY: 0.0000249 AC XY: 18AN XY: 723394 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152210Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 74340 show subpopulations
ClinVar
Submissions by phenotype
not specified Uncertain:1
Variant summary: SCN4A c.3002G>A (p.Arg1001His) results in a non-conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 2e-05 in 244522 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.3002G>A in individuals affected with Acetazolamide-Responsive Myotonia and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 566236). Based on the evidence outlined above, the variant was classified as uncertain significance. -
Familial hyperkalemic periodic paralysis Uncertain:1
This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 1001 of the SCN4A protein (p.Arg1001His). This variant is present in population databases (rs770588235, gnomAD 0.01%). 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: 566236). 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) performed at Invitae 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. -
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;C3714580:Hypokalemic periodic paralysis, type 1 Uncertain:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at