rs16866475

Variant names:

• chr2-178727602-G-A
• rs16866475
• NM_001267550.2:c.19976C>T

Your query was ambiguous. Multiple possible variants found:

• chr2-178727602-G-A
• chr2-178727602-G-T

Variant summary

Our verdict is Benign. Variant got -16 ACMG points: 0P and 16B. BP6_Very_Strong BS1 BS2

The NM_001267550.2(TTN):​c.19976C>T​(p.Thr6659Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00226 in 1,579,350 control chromosomes in the GnomAD database, including 73 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.012 (42 hom., cov: 33)
  • Exomes 𝑓: 0.0012 (31 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:23
• Conservation: PhyloP100: 8.13

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 -16 ACMG points.

• BP6: Variant 2-178727602-G-A is Benign according to our data. Variant chr2-178727602-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 46664.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178727602-G-A is described in Lovd as [Benign]. Variant chr2-178727602-G-A is described in Lovd as [Likely_benign].
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.0119 (1809/152124) while in subpopulation AFR AF= 0.0417 (1731/41518). AF 95% confidence interval is 0.0401. There are 42 homozygotes in gnomad4. There are 833 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.
• BS2: High Homozygotes in GnomAd4 at 42 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.19976C>T	p.Thr6659Met	missense_variant	Exon 68 of 363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.19976C>T	p.Thr6659Met	missense_variant	Exon 68 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.0119 AC: 1809 AN: 152006 Hom.: 42 Cov.: 33

Gnomad AFR AF: 0.0418

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00354

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: 0.000118

Gnomad OTH AF: 0.00766

GnomAD3 exomes AF: 0.00318 AC: 716 AN: 225194 Hom.: 10 AF XY: 0.00243 AC XY: 296 AN XY: 121904

Gnomad AFR exome AF: 0.0431

Gnomad AMR exome AF: 0.00169

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000801

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000862

Gnomad OTH exome AF: 0.000739

GnomAD4 exome AF: 0.00123 AC: 1754 AN: 1427226 Hom.: 31 Cov.: 31 AF XY: 0.00107 AC XY: 759 AN XY: 706604

Gnomad4 AFR exome AF: 0.0446

Gnomad4 AMR exome AF: 0.00226

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000752

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000639

Gnomad4 OTH exome AF: 0.00264

GnomAD4 genome AF: 0.0119 AC: 1809 AN: 152124 Hom.: 42 Cov.: 33 AF XY: 0.0112 AC XY: 833 AN XY: 74368

Gnomad4 AFR AF: 0.0417

Gnomad4 AMR AF: 0.00354

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000118

Gnomad4 OTH AF: 0.00758

Alfa AF: 0.00212 Hom.: 10

Bravo AF: 0.0139

TwinsUK AF: 0.00 AC: 0

ALSPAC AF: 0.000259 AC: 1

ESP6500AA AF: 0.0352 AC: 145

ESP6500EA AF: 0.000237 AC: 2

ExAC AF: 0.00374 AC: 452

Asia WGS AF: 0.00202 AC: 7 AN: 3478

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:23

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:9

Jul 03, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

3.5% (145/4124) of Afr Amer chrom from ESP -

Nov 21, 2021

Genetic Services Laboratory, University of Chicago

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 07, 2021

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

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

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

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jun 03, 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. -

Mar 12, 2020

Athena Diagnostics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jun 24, 2013

Biesecker Lab/Clinical Genomics Section, National Institutes of Health

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: research

- -

-

Clinical Genetics, Academic Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

not provided Benign:3

Nov 06, 2023

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

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

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

Breakthrough Genomics, Breakthrough Genomics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: not provided

- -

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 04, 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. -

Cardiovascular phenotype Benign:1

Oct 17, 2013

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	0.21
BayesDel_addAF	Benign	-0.33	T
BayesDel_noAF	Benign	-0.21
CADD	Uncertain	24
DANN	Benign	0.90
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.77	T;T;.;T
MetaRNN	Benign	0.0030	T;T;T;T
MetaSVM	Benign	-0.49	T
PrimateAI	Uncertain	0.53	T
PROVEAN	Uncertain	-3.4	D;.;.;.
REVEL	Uncertain	0.45
Sift	Benign	0.12	T;.;.;.
Polyphen		1.0	.;.;D;D
Vest4		0.17
MVP		0.84
MPC		0.46
ClinPred		0.020	T
GERP RS		6.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.22		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.22		Position offset: -17

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs16866475; hg19: chr2-179592329; COSMIC: COSV99045526; COSMIC: COSV99045526;