rs199933920

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2PP3_Strong

The NM_001365536.1(SCN9A):c.76C>T(p.Arg26Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000812 in 1,613,090 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R26H) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 30)

Exomes 𝑓: 0.000085 ( 0 hom. )

Consequence

SCN9A
NM_001365536.1 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 3.47

Variant links:

Genes affected

SCN9A (HGNC:10597): (sodium voltage-gated channel alpha subunit 9) This gene encodes a voltage-gated sodium channel which plays a significant role in nociception signaling. Mutations in this gene have been associated with primary erythermalgia, channelopathy-associated insensitivity to pain, and paroxysmal extreme pain disorder. [provided by RefSeq, Aug 2009]

SCN9A links:

SCN1A-AS1 (HGNC:54069): (SCN1A and SCN9A antisense RNA 1)

SCN1A-AS1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.96

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SCN9A	NM_001365536.1 linkuse as main transcript	c.76C>T	p.Arg26Cys	missense_variant	2/27	ENST00000642356.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SCN9A	ENST00000642356.2 linkuse as main transcript	c.76C>T	p.Arg26Cys	missense_variant	2/27		NM_001365536.1	P1	Q15858-1
SCN1A-AS1	ENST00000651574.1 linkuse as main transcript	n.1977+15552G>A		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.0000461

AC:

AN:

151702

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000484

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:

0.0000736

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000401

AC:

AN:

249142

Hom.:

AF XY:

0.0000666

AC XY:

AN XY:

135168

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000981

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000531

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000849

AC:

124

AN:

1461388

Hom.:

Cov.:

AF XY:

0.0000922

AC XY:

AN XY:

727002

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000348

Gnomad4 FIN exome

AF:

0.0000187

Gnomad4 NFE exome

AF:

0.000104

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.0000461

AC:

AN:

151702

Hom.:

Cov.:

AF XY:

0.0000405

AC XY:

AN XY:

74038

show subpopulations

Gnomad4 AFR

AF:

0.0000484

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000736

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000847

Hom.:

Bravo

AF:

0.0000302

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000120

AC:

ExAC

AF:

0.0000414

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.000237

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 23, 2019

The p.R26C variant (also known as c.76C>T), located in coding exon 1 of the SCN9A gene, results from a C to T substitution at nucleotide position 76. The arginine at codon 26 is replaced by cysteine, an amino acid with highly dissimilar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Generalized epilepsy with febrile seizures plus, type 7;C2752089:Neuropathy, hereditary sensory and autonomic, type 2A

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 30, 2023

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 26 of the SCN9A protein (p.Arg26Cys). This variant is present in population databases (rs199933920, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with SCN9A-related conditions. ClinVar contains an entry for this variant (Variation ID: 245873). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on SCN9A protein function. 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. -

Primary erythromelalgia;C1833661:Paroxysmal extreme pain disorder;C1855739:Channelopathy-associated congenital insensitivity to pain, autosomal recessive;C2752089:Neuropathy, hereditary sensory and autonomic, type 2A

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

May 19, 2022

- -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Aug 28, 2015

The R26C variant has not been published as pathogenic, nor has it been reported as a benign polymorphism to our knowledge. It was not observed with any significant frequency in approximately 6,000 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project. The R26C variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved across species, and in silico analysis predicts this variant is probably damaging to the protein structure/function. However, missense variants in nearby residues have not been reported in association with SCN9A-related disorders (Stenson et al., 2014). Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic variant or a rare benign variant. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.18

BayesDel_addAF

Pathogenic

0.37

BayesDel_noAF

Pathogenic

0.50

Cadd

Pathogenic

Dann

Pathogenic

1.0

Eigen

Pathogenic

0.88

Eigen_PC

Pathogenic

0.80

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Uncertain

0.91

D;.;D;D;D;D;D;D

M_CAP

Uncertain

0.15

MetaRNN

Pathogenic

0.96

D;D;D;D;D;D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

3.9

H;H;H;.;H;H;.;.

MutationTaster

Benign

1.0

D;D;D;D

PrimateAI

Uncertain

0.49

PROVEAN

Pathogenic

-7.3

D;D;.;.;.;D;.;.

REVEL

Pathogenic

0.89

Sift

Pathogenic

0.0

D;D;.;.;.;D;.;.

Sift4G

Pathogenic

0.0

D;D;.;.;.;D;.;.

Vest4

0.73

MVP

0.84

MPC

0.33

ClinPred

0.99

GERP RS

5.4

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.59

gMVP

0.52

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over