rs368256039
Variant summary
Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1PP3_StrongPP5
The NM_000334.4(SCN4A):c.4378C>T(p.Arg1460Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000211 in 1,612,890 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_000334.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_pathogenic. Variant got 7 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152212Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000200 AC: 5AN: 249680Hom.: 0 AF XY: 0.0000296 AC XY: 4AN XY: 135314
GnomAD4 exome AF: 0.0000219 AC: 32AN: 1460678Hom.: 0 Cov.: 35 AF XY: 0.0000220 AC XY: 16AN XY: 726424
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152212Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 74360
ClinVar
Submissions by phenotype
not provided Pathogenic:2
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Published functional studies showed altered voltage dependence and channel inactivation (Elia et al., 2019); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 30824560) -
SCN4A-related disorder Pathogenic:1
The SCN4A c.4378C>T variant is predicted to result in the amino acid substitution p.Arg1460Trp. This variant has been reported in the homozygous state in an individual with autosomal recessive congenital myasthenic syndrome and both parents of this individual are asymptomatic carriers (Table 1, Elia et al 2019. PubMed ID: 30824560). This variant is reported in 0.0065% of alleles in individuals of South Asian descent in gnomAD (http://gnomad.broadinstitute.org/variant/17-62019264-G-A). An alternate change affecting the same amino acid (p.Arg1460Gln) has been reported in the compound heterozygous state in an individual with autosomal recessive congenital myasthenic syndrome, as well as in the heterozygous state in multiple individuals with myotonia (Elia et al 2019. PubMed ID: 30824560). Functional studies of the alternate change, p.Arg1460Gln, have shown unusual mixed defects with both loss-of function and gain-of-function changes (Elia et al 2019. PubMed ID: 30824560). The c.4378C>T (p.Arg1460Trp) variant is interpreted as likely pathogenic. -
Hyperkalemic periodic paralysis Uncertain:1
This missense change has been observed in individual(s) with autosomal recessive SCN4A-related conditions (PMID: 30824560). 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. Experimental studies have shown that this missense change affects SCN4A function (PMID: 30824560). 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 expected to disrupt SCN4A protein function. ClinVar contains an entry for this variant (Variation ID: 477422). This variant is present in population databases (rs368256039, gnomAD 0.006%). This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 1460 of the SCN4A protein (p.Arg1460Trp). -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at