rs368282893

Variant names:

• chr2-178782297-C-T
• rs368282893
• NM_001267550.2:c.3295G>A

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 0P and 3B. BP4_Moderate BP6

The NM_001267550.2(TTN):​c.3295G>A​(p.Val1099Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000589 in 1,614,094 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000058 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:10 B:3
• Conservation: PhyloP100: 0.273

Genes affected

TTN (HGNC:12403): (titin) This gene encodes a large abundant protein of striated muscle. The product of this gene is divided into two regions, a N-terminal I-band and a C-terminal A-band. The I-band, which is the elastic part of the molecule, contains two regions of tandem immunoglobulin domains on either side of a PEVK region that is rich in proline, glutamate, valine and lysine. The A-band, which is thought to act as a protein-ruler, contains a mixture of immunoglobulin and fibronectin repeats, and possesses kinase activity. An N-terminal Z-disc region and a C-terminal M-line region bind to the Z-line and M-line of the sarcomere, respectively, so that a single titin molecule spans half the length of a sarcomere. Titin also contains binding sites for muscle associated proteins so it serves as an adhesion template for the assembly of contractile machinery in muscle cells. It has also been identified as a structural protein for chromosomes. Alternative splicing of this gene results in multiple transcript variants. Considerable variability exists in the I-band, the M-line and the Z-disc regions of titin. Variability in the I-band region contributes to the differences in elasticity of different titin isoforms and, therefore, to the differences in elasticity of different muscle types. Mutations in this gene are associated with familial hypertrophic cardiomyopathy 9, and autoantibodies to titin are produced in patients with the autoimmune disease scleroderma. [provided by RefSeq, Feb 2012]

ACMG classification

Verdict is Likely_benign. Variant got -3 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.12415156).
• BP6: Variant 2-178782297-C-T is Benign according to our data. Variant chr2-178782297-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 46938.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=3, Uncertain_significance=7}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.3295G>A	p.Val1099Met	missense_variant	Exon 20 of 363	ENST00000589042.5	NP_001254479.2
TTN	NM_133379.5	c.3295G>A	p.Val1099Met	missense_variant	Exon 20 of 46	ENST00000360870.10	NP_596870.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.3295G>A	p.Val1099Met	missense_variant	Exon 20 of 363	5	NM_001267550.2	ENSP00000467141.1
TTN	ENST00000360870.10	c.3295G>A	p.Val1099Met	missense_variant	Exon 20 of 46	5	NM_133379.5	ENSP00000354117.4

Frequencies

GnomAD3 genomes AF: 0.0000592 AC: 9 AN: 152140 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000965

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: 0.0000735

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000319 AC: 8 AN: 251106 Hom.: 0 AF XY: 0.0000368 AC XY: 5 AN XY: 135692

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000868

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000441

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000581 AC: 85 AN: 1461836 Hom.: 0 Cov.: 32 AF XY: 0.0000564 AC XY: 41 AN XY: 727218

Gnomad4 AFR exome AF: 0.000119

Gnomad4 AMR exome AF: 0.0000671

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000630

Gnomad4 OTH exome AF: 0.0000662

GnomAD4 genome AF: 0.0000657 AC: 10 AN: 152258 Hom.: 0 Cov.: 32 AF XY: 0.0000940 AC XY: 7 AN XY: 74450

Gnomad4 AFR AF: 0.000120

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: 0.0000735

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000533 Hom.: 0

Bravo AF: 0.0000945

ESP6500AA AF: 0.000227 AC: 1

ESP6500EA AF: 0.000116 AC: 1

ExAC AF: 0.0000247 AC: 3

EpiCase AF: 0.000109

EpiControl AF: 0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:10 Benign:3

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:3 Benign:1

-

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Dec 09, 2020

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Genome Diagnostics Laboratory, Amsterdam University Medical Center

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

Clinical Genetics, Academic Medical Center

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Dilated cardiomyopathy 1G Uncertain:2

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Jan 04, 2025

Genomic Medicine Center of Excellence, King Faisal Specialist Hospital and Research Centre

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not specified Uncertain:1

Jan 25, 2019

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant classified as Uncertain Significance - Favor Benign. Disclaimer: This variant has not undergone full assessment. The following are preliminary notes: Not reported in the literature. LB to VUS in ClinVar. Identified in 9/282508 chromosomes in gnomAD. -

Autosomal recessive limb-girdle muscular dystrophy type 2J Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Uncertain:1

Oct 13, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Early-onset myopathy with fatal cardiomyopathy Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Primary dilated cardiomyopathy Uncertain:1

-

Genetics and Genomics Program, Sidra Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: research

- -

Tibial muscular dystrophy Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Myopathy, myofibrillar, 9, with early respiratory failure Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.26
BayesDel_addAF	Benign	-0.30	T
BayesDel_noAF	Benign	-0.48
CADD	Benign	12
DANN	Benign	0.90
Eigen	Benign	-0.27
Eigen_PC	Benign	-0.47
FATHMM_MKL	Benign	0.18	N
LIST_S2	Uncertain	0.97	D;D;D;.;D;D;D;D
M_CAP	Benign	0.038	D
MetaRNN	Benign	0.12	T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.72	T
PrimateAI	Benign	0.29	T
PROVEAN	Benign	-2.0	N;N;.;.;N;N;.;D
REVEL	Benign	0.20
Sift	Uncertain	0.010	D;D;.;.;D;D;.;D
Sift4G	Pathogenic	0.0010	.;.;.;.;.;.;.;D
Polyphen		0.91, 0.99	.;.;.;P;.;.;P;D
Vest4		0.31
MVP		0.27
MPC		0.23
ClinPred		0.11	T
GERP RS		-2.6

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs368282893; hg19: chr2-179647024; COSMIC: COSV104415630; COSMIC: COSV104415630;