17-63941940-G-T

Variant names:

• chr17-63941940-G-T
• rs121908544
• NM_000334.4:c.4342C>A

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_000334.4(SCN4A):​c.4342C>A​(p.Arg1448Ser) variant causes a missense change involving the alteration of a non-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 not provided (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1448C) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: SCN4A NM_000334.4 missense
• Clinical Significance: not provided no classification provided O:1
• Conservation: PhyloP100: 3.02

Genes affected

SCN4A (HGNC:10591): (sodium voltage-gated channel alpha subunit 4) Voltage-gated sodium channels are transmembrane glycoprotein complexes composed of a large alpha subunit with 24 transmembrane domains and one or more regulatory beta subunits. They are responsible for the generation and propagation of action potentials in neurons and muscle. This gene encodes one member of the sodium channel alpha subunit gene family. It is expressed in skeletal muscle, and mutations in this gene have been linked to several myotonia and periodic paralysis disorders. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PM1: In a transmembrane_region Helical; Name=S4 of repeat IV (size 16) in uniprot entity SCN4A_HUMAN there are 9 pathogenic changes around while only 0 benign (100%) in NM_000334.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-63941940-G-A is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN4A	NM_000334.4	c.4342C>A	p.Arg1448Ser	missense_variant	Exon 24 of 24	ENST00000435607.3	NP_000325.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN4A	ENST00000435607.3	c.4342C>A	p.Arg1448Ser	missense_variant	Exon 24 of 24	1	NM_000334.4	ENSP00000396320.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 31

ClinVar

Significance: not provided

Submissions summary: Other:1

Revision: no classification provided

Submissions by phenotype

Hyperkalemic periodic paralysis Other:1

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GeneReviews

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.50	D
BayesDel_noAF	Pathogenic	0.49
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.96	D
Eigen	Uncertain	0.54
Eigen_PC	Uncertain	0.44
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.64	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Benign	1.8	L
PrimateAI	Pathogenic	0.88	D
PROVEAN	Pathogenic	-5.6	D
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.89
MutPred		0.97		Loss of MoRF binding (P = 0.032);
MVP		0.96
MPC		0.86
ClinPred		1.0	D
GERP RS		3.7
Varity_R		0.96
gMVP		0.92

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs121908544; hg19: chr17-62019300;