rs80338789

Variant names:

• chr17-63947091-C-T
• rs80338789
• NM_000334.4:c.3395G>A

Variant summary

Our verdict is Pathogenic. The variant received 21 ACMG points: 21P and 0B. PS3 PM1 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000334.4(SCN4A):​c.3395G>A​(p.Arg1132Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,613,408 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV002577229: Published functional studies demonstrate this variant leads to abnormal depolarization of the sodium channel at resting potential leading to muscle hypo-excitability" and additional evidence is available in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1132G) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: SCN4A NM_000334.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:8 O:1
• Conservation: PhyloP100: 7.91
• Publications: 21 publications found

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]

SCN4A Gene-Disease associations (from GenCC):

• hyperkalemic periodic paralysis

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp, Orphanet
• paramyotonia congenita of Von Eulenburg

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Laboratory for Molecular Medicine
• SCN4A-related myopathy, autosomal recessive

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Illumina, ClinGen, PanelApp Australia
• hypokalemic periodic paralysis, type 2

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• potassium-aggravated myotonia

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• congenital myasthenic syndrome 16

  Inheritance: AR Classification: STRONG, LIMITED Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics
• congenital myopathy

  Inheritance: AR Classification: STRONG Submitted by: Genomics England PanelApp
• congenital myopathy 22A, classic

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• acetazolamide-responsive myotonia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• hypokalemic periodic paralysis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• myotonia fluctuans

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• myotonia permanens

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• postsynaptic congenital myasthenic syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 21 ACMG points.

• PS3: PS3 evidence extracted from ClinVar submissions: SCV002577229: Published functional studies demonstrate this variant leads to abnormal depolarization of the sodium channel at resting potential leading to muscle hypo-excitability; It also alters channel activation and deactivation (Carle et al., 2006; Francis et al., 2011; Mnnikk et al., 2018); SCV000819816: Experimental studies have shown that this missense change affects SCN4A function (PMID: 16890191, 21490317).; SCV001338320: "At least two functional studies report this variant conducts an anomalous gating pore current (Carle_2006, Francis_2011)."
• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in NM_000334.4
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-63947092-G-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1039768.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 97 curated pathogenic missense variants (we use a threshold of 10). The gene has 19 curated benign missense variants. Gene score misZ: 1.5606 (below the threshold of 3.09). Trascript score misZ: 2.2224 (below the threshold of 3.09). GenCC associations: The gene is linked to SCN4A-related myopathy, autosomal recessive, hyperkalemic periodic paralysis, paramyotonia congenita of Von Eulenburg, congenital myasthenic syndrome 16, acetazolamide-responsive myotonia, myotonia permanens, hypokalemic periodic paralysis, type 2, potassium-aggravated myotonia, congenital myopathy 22A, classic, congenital myopathy, myotonia fluctuans, postsynaptic congenital myasthenic syndrome, hypokalemic periodic paralysis.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993
• PP5: Variant 17-63947091-C-T is Pathogenic according to our data. Variant chr17-63947091-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 21155.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000334.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SCN4A	NM_000334.4	MANE Select	c.3395G>A	p.Arg1132Gln	missense	Exon 18 of 24	NP_000325.4	P35499

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SCN4A	ENST00000435607.3	TSL:1 MANE Select	c.3395G>A	p.Arg1132Gln	missense	Exon 18 of 24	ENSP00000396320.1	P35499

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152106 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461302 Hom.: 0 Cov.: 36 AF XY: 0.00000138 AC XY: 1 AN XY: 726946

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44712

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53182

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5704

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111784

Other (OTH) AF: 0.0000166 AC: 1 AN: 60354

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152106 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74310

African (AFR) AF: 0.00 AC: 0 AN: 41406

American (AMR) AF: 0.00 AC: 0 AN: 15276

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5188

South Asian (SAS) AF: 0.00 AC: 0 AN: 4820

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10622

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 68002

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.0000254 Hom.: 0

Bravo AF: 0.00000756

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
3	-	-	not provided (3)
2	-	-	Hypokalemic periodic paralysis, type 2 (3)
1	-	-	Hyperkalemic periodic paralysis (1)
1	-	-	not specified (1)
1	-	-	Skeletal muscle channelopathy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	30
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.98	D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Benign	0.73	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Pathogenic	0.73	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Pathogenic	5.7	H
PhyloP100		7.9
PrimateAI	Pathogenic	0.82	D
PROVEAN	Uncertain	-3.8	D
REVEL	Pathogenic	0.93
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.98
MutPred		0.96		Loss of methylation at R1132 (P = 0.0069)
MVP		0.96
MPC		0.89
ClinPred		1.0	D
GERP RS		4.1
Varity_R		0.79
gMVP		0.96
Mutation Taster		=3/97	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs80338789; hg19: chr17-62024451;