17-63945614-C-T

Variant names:

• chr17-63945614-C-T
• rs80338958
• NM_000334.4:c.3466G>A

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PS3 PM1 PP2 PP3_Moderate PP5_Very_Strong

The NM_000334.4(SCN4A):​c.3466G>A​(p.Ala1156Thr) variant causes a missense change. The variant allele was found at a frequency of 0.0000347 in 1,613,762 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 Likely pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV001206949: Experimental studies have shown that this missense change affects SCN4A function (PMID:7809121, 28330959)." and additional evidence is available in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A1156S) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000033 (0 hom., cov: 31)
  • Exomes 𝑓: 0.000035 (0 hom.)
• Consequence: SCN4A NM_000334.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:13
• Conservation: PhyloP100: 6.08
• Publications: 26 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 17 ACMG points.

• PS3: PS3 evidence extracted from ClinVar submissions: SCV001206949: Experimental studies have shown that this missense change affects SCN4A function (PMID: 7809121, 28330959).; SCV002520120: Published functional studies demonstrate that this variant results in altered channel inactivation and voltage dependence compared to wild-type controls (Yang et al., 1994; Hayward et al., 1999; Palmio et al., 2017); SCV003862265: Functional analysis demonstrated that the p.A1156T alteration exhibited a disturbance in channel inactivation compared to the wild-type (Yang, 1994; Palmio, 2017).; SCV004046438: Functional studies showed that the c.3466G>A (p.Ala1156Thr) variant resulted in mild attenuation and disturbance of channel inactivation due to reduced macroscopic rate, accelerated recovery, and altered voltage dependence (PMID: 1338909, 7809121, 28330959).; SCV005088892: Functional studies using invitro transfection assays showed fast inactivation in cells harboring variant p.A1156T channel was mildly attenuated in comparison to cells with wild-type channel suggesting the gain of function. PMID:28330959
• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000334.4
• 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, 0.915
• PP5: Variant 17-63945614-C-T is Pathogenic according to our data. Variant chr17-63945614-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 5900.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.3466G>A	p.Ala1156Thr	missense	Exon 19 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.3466G>A	p.Ala1156Thr	missense	Exon 19 of 24	ENSP00000396320.1	P35499

Frequencies

GnomAD3 genomes AF: 0.0000329 AC: 5 AN: 152050 Hom.: 0 Cov.: 31

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: 0.000283

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000559 AC: 14 AN: 250384 AF XY: 0.0000516

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.000463

Gnomad NFE exome AF: 0.0000265

Gnomad OTH exome AF: 0.000164

GnomAD4 exome AF: 0.0000349 AC: 51 AN: 1461712 Hom.: 0 Cov.: 34 AF XY: 0.0000385 AC XY: 28 AN XY: 727150

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

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

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

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86258

European-Finnish (FIN) AF: 0.000656 AC: 35 AN: 53388

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000989 AC: 11 AN: 1111890

Other (OTH) AF: 0.0000663 AC: 4 AN: 60374

GnomAD4 genome AF: 0.0000329 AC: 5 AN: 152050 Hom.: 0 Cov.: 31 AF XY: 0.0000269 AC XY: 2 AN XY: 74262

African (AFR) AF: 0.00 AC: 0 AN: 41370

American (AMR) AF: 0.00 AC: 0 AN: 15262

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5192

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.000283 AC: 3 AN: 10606

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: 0.0000845 Hom.: 1

Bravo AF: 0.0000227

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000116 AC: 1

ExAC AF: 0.0000577 AC: 7

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
5	-	-	not provided (5)
2	-	-	Hyperkalemic periodic paralysis (2)
1	-	-	Focal-onset seizure (1)
1	-	-	Inborn genetic diseases (1)
1	-	-	Paramyotonia congenita of Von Eulenburg;C0238357:Hyperkalemic periodic paralysis;C2750061:Hypokalemic periodic paralysis, type 2;C2931826:Potassium-aggravated myotonia;C3280112:Congenital myasthenic syndrome 16;C3714580:Hypokalemic periodic paralysis, type 1 (1)
1	-	-	Paramyotonia congenita/hyperkalemic periodic paralysis (1)
1	-	-	Potassium-aggravated myotonia (1)
1	-	-	SCN4A-related disorder (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	28
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.96	D
Eigen	Pathogenic	0.71
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Uncertain	0.96	D
M_CAP	Pathogenic	0.53	D
MetaRNN	Pathogenic	0.91	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.1	M
PhyloP100		6.1
PrimateAI	Pathogenic	0.89	D
PROVEAN	Uncertain	-3.8	D
REVEL	Pathogenic	0.90
Sift	Pathogenic	0.0	D
Sift4G	Benign	0.078	T
Polyphen		1.0	D
Vest4		0.87
MVP		0.95
MPC		0.89
ClinPred		0.81	D
GERP RS		3.9
Varity_R		0.87
gMVP		0.91
Mutation Taster		=1/99	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: rs80338958; hg19: chr17-62022974;