NM_001267550.2:c.19204A>G

Variant names:

• chr2-178728722-T-C
• rs72648954
• NM_001267550.2:c.19204A>G

Variant summary

Our verdict is Benign. Variant got -20 ACMG points: 0P and 20B. BP4_Strong BP6_Very_Strong BS1 BS2

The NM_001267550.2(TTN):​c.19204A>G​(p.Met6402Val) variant causes a missense change. The variant allele was found at a frequency of 0.00312 in 1,611,378 control chromosomes in the GnomAD database, including 113 homozygotes. In-silico tool predicts a benign outcome for this variant. 12/17 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.015 (57 hom., cov: 33)
  • Exomes 𝑓: 0.0019 (56 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:25
• Conservation: PhyloP100: 4.99

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]

TTN-AS1 (HGNC:44124): (TTN antisense RNA 1) This gene encodes a non-coding RNA transcribed from the opposite strand to the titin gene. [provided by RefSeq, Aug 2016]

ACMG classification

Verdict is Benign. Variant got -20 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.0014709234).
• BP6: Variant 2-178728722-T-C is Benign according to our data. Variant chr2-178728722-T-C is described in ClinVar as [Likely_benign]. Clinvar id is 46655.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178728722-T-C is described in Lovd as [Benign]. Variant chr2-178728722-T-C is described in Lovd as [Likely_benign].
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.0153 (2329/152292) while in subpopulation AFR AF= 0.0516 (2147/41576). AF 95% confidence interval is 0.0498. There are 57 homozygotes in gnomad4. There are 1073 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.
• BS2: High Homozygotes in GnomAd4 at 57 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.19204A>G	p.Met6402Val	missense_variant	Exon 66 of 363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.19204A>G	p.Met6402Val	missense_variant	Exon 66 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.0153 AC: 2327 AN: 152174 Hom.: 58 Cov.: 33

Gnomad AFR AF: 0.0517

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00662

Gnomad ASJ AF: 0.00634

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00949

Gnomad NFE AF: 0.000338

Gnomad OTH AF: 0.0153

GnomAD3 exomes AF: 0.00410 AC: 1018 AN: 248182 Hom.: 28 AF XY: 0.00298 AC XY: 401 AN XY: 134614

Gnomad AFR exome AF: 0.0515

Gnomad AMR exome AF: 0.00291

Gnomad ASJ exome AF: 0.00489

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.000131

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000463

Gnomad OTH exome AF: 0.00283

GnomAD4 exome AF: 0.00185 AC: 2704 AN: 1459086 Hom.: 56 Cov.: 32 AF XY: 0.00162 AC XY: 1172 AN XY: 725286

Gnomad4 AFR exome AF: 0.0505

Gnomad4 AMR exome AF: 0.00358

Gnomad4 ASJ exome AF: 0.00594

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.000128

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.000354

Gnomad4 OTH exome AF: 0.00461

GnomAD4 genome AF: 0.0153 AC: 2329 AN: 152292 Hom.: 57 Cov.: 33 AF XY: 0.0144 AC XY: 1073 AN XY: 74454

Gnomad4 AFR AF: 0.0516

Gnomad4 AMR AF: 0.00661

Gnomad4 ASJ AF: 0.00634

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000207

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000338

Gnomad4 OTH AF: 0.0151

Alfa AF: 0.00314 Hom.: 13

Bravo AF: 0.0174

TwinsUK AF: 0.00 AC: 0

ALSPAC AF: 0.000259 AC: 1

ESP6500AA AF: 0.0440 AC: 165

ESP6500EA AF: 0.000486 AC: 4

ExAC AF: 0.00484 AC: 585

Asia WGS AF: 0.00289 AC: 10 AN: 3478

EpiCase AF: 0.000601

EpiControl AF: 0.000475

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:25

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:8

-

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

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Mar 26, 2014

GeneDx

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

Aug 15, 2013

Genetic Services Laboratory, University of Chicago

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Clinical Genetics, Academic Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Mar 28, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jul 06, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

4.4% (165/3748) in Afr Amer chrom from ESP -

Jun 24, 2013

Biesecker Lab/Clinical Genomics Section, National Institutes of Health

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: research

- -

-

PreventionGenetics, part of Exact Sciences

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Benign:5

-

Breakthrough Genomics, Breakthrough Genomics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: not provided

- -

-

Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

May 09, 2019

Athena Diagnostics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dec 21, 2022

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J Benign:2

Sep 10, 2021

Genome-Nilou Lab

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: 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 benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Early-onset myopathy with fatal cardiomyopathy Benign:2

Sep 10, 2021

Genome-Nilou Lab

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: 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 benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Tibial muscular dystrophy Benign:2

Sep 10, 2021

Genome-Nilou Lab

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: 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 benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Myopathy, myofibrillar, 9, with early respiratory failure Benign:2

Sep 10, 2021

Genome-Nilou Lab

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: 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 benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

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

Feb 03, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dilated cardiomyopathy 1G Benign:1

Jan 13, 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. -

Cardiomyopathy Benign:1

Mar 02, 2016

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

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cardiovascular phenotype Benign:1

Dec 14, 2012

Ambry Genetics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as benign based on a combination of the following: 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

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.047
BayesDel_addAF	Benign	-0.62	T
BayesDel_noAF	Benign	-0.63
CADD	Benign	17
DANN	Benign	0.83
Eigen	Benign	-0.54
Eigen_PC	Benign	-0.24
FATHMM_MKL	Benign	0.11	N
LIST_S2	Benign	0.45	T;T;.;T
MetaRNN	Benign	0.0015	T;T;T;T
MetaSVM	Benign	-1.0	T
PrimateAI	Benign	0.33	T
PROVEAN	Benign	0.92	N;.;.;.
REVEL	Benign	0.10
Sift	Benign	0.64	T;.;.;.
Polyphen		0.0	.;.;B;B
Vest4		0.094
MVP		0.088
MPC		0.085
ClinPred		0.0020	T
GERP RS		4.8

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs72648954; hg19: chr2-179593449;