1-77926510-C-T

Variant summary

Our verdict is Benign. Variant got -7 ACMG points: 0P and 7B. BP4_ModerateBS1_SupportingBS2

The NM_144573.4(NEXN):c.586C>T(p.Arg196Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000447 in 1,611,544 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign 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. R196H) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00049 ( 0 hom. )

Consequence

NEXN
NM_144573.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:7

Conservation

PhyloP100: 0.205

Variant links:

Genes affected

NEXN (HGNC:29557): (nexilin F-actin binding protein) This gene encodes a filamentous actin-binding protein that may function in cell adhesion and migration. Mutations in this gene have been associated with dilated cardiomyopathy, also known as CMD1CC. Alternatively spliced transcript variants have been described.[provided by RefSeq, Feb 2010]

NEXN links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -7 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.15044531).

BS1

Variant frequency is greater than expected in population nfe. gnomad4_exome allele frequency = 0.000487 (711/1459918) while in subpopulation NFE AF= 0.000621 (690/1111136). AF 95% confidence interval is 0.000582. There are 0 homozygotes in gnomad4_exome. There are 326 alleles in male gnomad4_exome subpopulation. Median coverage is 31. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

BS2

High AC in GnomAd at 10 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NEXN	NM_144573.4 linkuse as main transcript	c.586C>T	p.Arg196Cys	missense_variant	7/13	ENST00000334785.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NEXN	ENST00000334785.12 linkuse as main transcript	c.586C>T	p.Arg196Cys	missense_variant	7/13	1	NM_144573.4	P3	Q0ZGT2-1

Frequencies

GnomAD3 genomes

AF:

0.0000660

AC:

AN:

151626

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000243

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:

0.000132

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000117

AC:

AN:

248438

Hom.:

AF XY:

0.000119

AC XY:

AN XY:

134800

show subpopulations

Gnomad AFR exome

AF:

0.0000646

Gnomad AMR exome

AF:

0.0000291

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000987

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000213

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000487

AC:

711

AN:

1459918

Hom.:

Cov.:

AF XY:

0.000449

AC XY:

326

AN XY:

726190

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000253

Gnomad4 SAS exome

AF:

0.000140

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.000621

Gnomad4 OTH exome

AF:

0.000116

GnomAD4 genome

AF:

0.0000660

AC:

AN:

151626

Hom.:

Cov.:

AF XY:

0.0000676

AC XY:

AN XY:

74008

show subpopulations

Gnomad4 AFR

AF:

0.0000243

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:

0.000132

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000900

Hom.:

Bravo

AF:

0.0000793

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.00

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000123

AC:

ExAC

AF:

0.0000828

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.000356

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Dilated cardiomyopathy 1CC;C3151267:Hypertrophic cardiomyopathy 20

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Aug 19, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Oct 05, 2022	This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 196 of the NEXN protein (p.Arg196Cys). This variant is present in population databases (rs369486891, gnomAD 0.02%). This missense change has been observed in individual(s) with dilated cardiomyopathy (PMID: 28333919, 31983221). ClinVar contains an entry for this variant (Variation ID: 179003). 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 NEXN 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. -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Jun 12, 2013

The Arg196Cys in NEXN has not been reported in individuals with cardiomyopathy, but has been identified in 1/8146 European American chromosomes by the NHLBI Exo me Sequencing Project (http://evs.gs.washington.edu/EVS/). The affected amino ac id is not well conserved in evolution, raising the possibility that a change wou ld be tolerated. Other computational analyses (biochemical amino acid propertie s, AlignGVGD, PolyPhen2, and SIFT) do not provide strong support for or against an impact to the protein. Additional information is needed to fully assess the c linical significance of this variant. -

Cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Jul 06, 2022

- -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jan 21, 2021

Reported in a patient with cardiomyopathy and atrial fibrillation who experienced sudden cardiac death, however, this patient also harbored a potentially disease-causing variant in the LMNA gene (Bagnall et al., 2017); Observed in association with dilated cardiomyopathy (Mazzarotto et al., 2020); however, specific clinical information was not provided; Reported in ClinVar as a variant of uncertain significance (ClinVar Variant ID# 179003; Landrum et al., 2016); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 30354306, 28333919, 31983221) -

Primary dilated cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Molecular Genetics, Royal Melbourne Hospital

Mar 30, 2023

This sequence change in NEXN is predicted to replace arginine with cysteine at codon 196, p.(Arg196Cys). The arginine residue is moderately conserved (100 vertebrates, UCSC), and is located in a coiled-coil region. There is a large physicochemical difference between arginine and cysteine. The highest population minor allele frequency in gnomAD v2.1 is 0.02% (24/128,070 alleles) in the European (non-Finnish) population. The prevalence of the variant in affected individuals is significantly increased compared with the prevalence in controls (odds ratio 4.9, 95% CI 1.2-20.7) (cases - PMID: 31983221; controls - European non-TOPMED gnomAD v2.1). This variant has been observed in at least two patients with an alternate molecular basis for disease, a long QT syndrome case with a de novo CALM2 variant and a dilated cardiomyopathy case with a pathogenic LMNA variant (PMID: 28333919, 30354306). Multiple lines of computational evidence have conflicting predictions for the missense substitution (4/6 algorithms predict deleterious). Based on the classification scheme RMH Modified ACMG Guidelines v1.4.0, this variant is classified as a VARIANT OF UNCERTAIN SIGNIFICANCE. Following criteria are met: PS4_Moderate, BP5. -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 08, 2020

The p.R196C variant (also known as c.586C>T), located in coding exon 6 of the NEXN gene, results from a C to T substitution at nucleotide position 586. The arginine at codon 196 is replaced by cysteine, an amino acid with highly dissimilar properties. This variant (described as p.R132C) has been reported in a sudden unexplained death case who had dilated cardiomyopathy, atrial fibrillation, and additional cardiac variants detected; this variant was not detected in his affected mother (Bagnall RD et al. Genet. Med., 2017 10;19:1127-1133). This variant was also detected in an individual with prolonged QTc and hypertrophic cardiomyopathy, who also had a reportedly de novo CALM2 variant and additional cardiac variants also detected (Zahavich L et al. Circ Genom Precis Med, 2018 10;11:e002255). This amino acid position is not well conserved in available vertebrate species, and cysteine is the reference amino acid in other vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.15

BayesDel_addAF

Benign

-0.21

BayesDel_noAF

Benign

-0.24

Cadd

Benign

Dann

Uncertain

0.99

DEOGEN2

Benign

0.37

T;.;T;T

Eigen

Benign

-0.41

Eigen_PC

Benign

-0.64

FATHMM_MKL

Benign

0.19

LIST_S2

Benign

0.76

T;T;T;T

M_CAP

Benign

0.080

MetaRNN

Benign

0.15

T;T;T;T

MetaSVM

Benign

-0.61

MutationTaster

Benign

0.99

N;N;N

PrimateAI

Benign

0.24

PROVEAN

Uncertain

-4.2

D;N;N;D

REVEL

Benign

0.21

Sift

Uncertain

0.018

D;D;D;D

Sift4G

Uncertain

0.0040

D;D;D;D

Polyphen

1.0

.;.;D;.

Vest4

0.27, 0.22

MVP

0.63

MPC

0.27

ClinPred

0.28

GERP RS

-2.2

Varity_R

0.058

gMVP

0.21

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