1-77935986-CAAG-C

Variant names:

• chr1-77935986-CAAG-C
• rs794729091
• NM_144573.4:c.1419_1421delAAG

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 1P and 5B. PM4_Supporting BS1_Supporting BS2

The NM_144573.4(NEXN):​c.1419_1421delAAG​(p.Arg474del) variant causes a disruptive inframe deletion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000121 in 1,613,672 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. R473R) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.00013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00012 (0 hom.)
• Consequence: NEXN NM_144573.4 disruptive_inframe_deletion
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:7 B:1
• Conservation: PhyloP100: 2.09

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]

ACMG classification

Verdict is Likely_benign. Variant got -4 ACMG points.

• PM4: Nonframeshift variant in NON repetitive region in NM_144573.4. Strenght limited to Supporting due to length of the change: 1aa.
• BS1: Variant frequency is greater than expected in population nfe. gnomad4 allele frequency = 0.000132 (20/151988) while in subpopulation NFE AF= 0.000221 (15/68004). AF 95% confidence interval is 0.000135. There are 0 homozygotes in gnomad4. There are 7 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAd4 at 20 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NEXN	NM_144573.4	c.1419_1421delAAG	p.Arg474del	disruptive_inframe_deletion	Exon 11 of 13	ENST00000334785.12	NP_653174.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NEXN	ENST00000334785.12	c.1419_1421delAAG	p.Arg474del	disruptive_inframe_deletion	Exon 11 of 13	1	NM_144573.4	ENSP00000333938.7

Frequencies

GnomAD3 genomes AF: 0.000132 AC: 20 AN: 151988 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000725

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000656

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.0000946

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000221

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000173 AC: 43 AN: 249020 Hom.: 0 AF XY: 0.000207 AC XY: 28 AN XY: 135224

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000203

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000556

Gnomad SAS exome AF: 0.000196

Gnomad FIN exome AF: 0.0000464

Gnomad NFE exome AF: 0.000222

Gnomad OTH exome AF: 0.000496

GnomAD4 exome AF: 0.000120 AC: 176 AN: 1461684 Hom.: 0 AF XY: 0.000138 AC XY: 100 AN XY: 727132

Gnomad4 AFR exome AF: 0.0000598

Gnomad4 AMR exome AF: 0.000201

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000504

Gnomad4 SAS exome AF: 0.000174

Gnomad4 FIN exome AF: 0.0000187

Gnomad4 NFE exome AF: 0.000116

Gnomad4 OTH exome AF: 0.000182

GnomAD4 genome AF: 0.000132 AC: 20 AN: 151988 Hom.: 0 Cov.: 33 AF XY: 0.0000943 AC XY: 7 AN XY: 74236

Gnomad4 AFR AF: 0.0000725

Gnomad4 AMR AF: 0.0000656

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.0000946

Gnomad4 NFE AF: 0.000221

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000304 Hom.: 0

Bravo AF: 0.000170

EpiCase AF: 0.000273

EpiControl AF: 0.000415

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:7 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:2

Apr 03, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Reported in an individual with DCM (Gigli et al., 2019); described as c.1416_1418delAAG (p.Arg475del); In-frame deletion of one amino acid in a non-repeat region; In silico analysis supports a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 34426522, 31514951) -

Jan 23, 2023

Clinical Genetics Laboratory, Skane University Hospital Lund

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not specified Uncertain:1

May 22, 2013

Stanford Center for Inherited Cardiovascular Disease, Stanford University

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

Note this variant was found in clinical genetic testing performed by one or more labs who may also submit to ClinVar. Thus any internal case data may overlap with the internal case data of other labs. The interpretation reviewed below is that of the Stanford Center for Inherited Cardiovascular Disease. p. Arg474del (c.1419_1421delAAG) This variant is novel. This variant is located in exon 11 (coding exon 10) of the NEXN gene. The variant results from an in-frame AAG deletion between nucleotide position 1419 and 1421. This results in the deletion of an arginine residue at codon 474. The arginine at codon 474 is conserved across species, as are neighboring amino acids. In total the variant has not been seen in ~6,500 published controls and individuals from publicly available population datasets. There is no variation at codon 474 listed in the NHLBI Exome Sequencing Project dataset, which currently includes variant calls on ~6,500 Caucasian and African American individuals (as of 8/1/13). There is also no variation at this codon listed in dbSNP or 1000 genomes (as of 8/1/13). Ambry genetics did not include internal control data. -

Cardiomyopathy Uncertain:1

Mar 01, 2019

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

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Primary familial dilated cardiomyopathy Uncertain:1

-

Molecular Diagnostic Laboratory for Inherited Cardiovascular Disease, Montreal Heart Institute

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

NEXN-related disorder Uncertain:1

Jul 15, 2024

PreventionGenetics, part of Exact Sciences

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

The NEXN c.1419_1421delAAG variant is predicted to result in an in-frame deletion (p.Arg475del). This variant was reported in individuals with dilated cardiomyopathy or sudden death; however, no additional studies were performed to help assess the pathogenicity of this variant (Scheiper et al. 2018. PubMed ID: 30415094; Online supplementary file 2, van Lint et al. 2019. PubMed ID: 30847666; described as c.1416_1418delAAG in Online Table 1, Gigli et al. 2019. PubMed ID: 31514951). This variant is reported in 0.020% of alleles in individuals of European (Non-Finnish) descent in gnomAD and has conflicting interpretations of pathogenicity in ClinVar ranging from likely benign to uncertain (http://www.ncbi.nlm.nih.gov/clinvar/variation/201940). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Dilated cardiomyopathy 1CC;C3151267:Hypertrophic cardiomyopathy 20 Uncertain:1

Dec 11, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant, c.1419_1421del, results in the deletion of 1 amino acid(s) of the NEXN protein (p.Arg475del), but otherwise preserves the integrity of the reading frame. This variant is present in population databases (rs766608869, gnomAD 0.02%). This variant has been observed in individual(s) with dilated cardiomyopathy (PMID: 31514951). ClinVar contains an entry for this variant (Variation ID: 201940). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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. -

Cardiovascular phenotype Benign:1

Sep 23, 2020

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

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

Other links and lift over

dbSNP: rs794729091; hg19: chr1-78401671;