2-178571160-A-G

Variant names:

• chr2-178571160-A-G
• rs744427
• NM_001267550.2:c.74972T>C

Variant summary

Our verdict is Benign. Variant got -20 ACMG points: 0P and 20B. BP4_Strong BP6_Very_Strong BA1

The NM_001267550.2(TTN):​c.74972T>C​(p.Ile24991Thr) variant causes a missense change. The variant allele was found at a frequency of 0.00278 in 1,613,456 control chromosomes in the GnomAD database, including 109 homozygotes. In-silico tool predicts a benign outcome for this variant. 12/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.014 (49 hom., cov: 32)
  • Exomes 𝑓: 0.0016 (60 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:26
• Conservation: PhyloP100: 5.32

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=0.0044543445).
• BP6: Variant 2-178571160-A-G is Benign according to our data. Variant chr2-178571160-A-G is described in ClinVar as [Likely_benign]. Clinvar id is 47333.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178571160-A-G is described in Lovd as [Benign]. Variant chr2-178571160-A-G is described in Lovd as [Likely_benign].
• BA1: GnomAdExome4 highest subpopulation (AFR) allele frequency at 95% confidence interval = 0.0528 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.74972T>C	p.Ile24991Thr	missense_variant	Exon 326 of 363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.74972T>C	p.Ile24991Thr	missense_variant	Exon 326 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.0142 AC: 2162 AN: 152064 Hom.: 48 Cov.: 32

Gnomad AFR AF: 0.0497

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00446

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000194

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.0000943

Gnomad MID AF: 0.00316

Gnomad NFE AF: 0.000206

Gnomad OTH AF: 0.00812

GnomAD3 exomes AF: 0.00362 AC: 898 AN: 248160 Hom.: 23 AF XY: 0.00282 AC XY: 380 AN XY: 134602

Gnomad AFR exome AF: 0.0513

Gnomad AMR exome AF: 0.00203

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.000261

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000152

Gnomad OTH exome AF: 0.00149

GnomAD4 exome AF: 0.00159 AC: 2320 AN: 1461274 Hom.: 60 Cov.: 40 AF XY: 0.00136 AC XY: 992 AN XY: 726922

Gnomad4 AFR exome AF: 0.0549

Gnomad4 AMR exome AF: 0.00186

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.000197

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.000154

Gnomad4 OTH exome AF: 0.00333

GnomAD4 genome AF: 0.0143 AC: 2172 AN: 152182 Hom.: 49 Cov.: 32 AF XY: 0.0142 AC XY: 1058 AN XY: 74398

Gnomad4 AFR AF: 0.0498

Gnomad4 AMR AF: 0.00445

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000194

Gnomad4 SAS AF: 0.000207

Gnomad4 FIN AF: 0.0000943

Gnomad4 NFE AF: 0.000206

Gnomad4 OTH AF: 0.00803

Alfa AF: 0.00495 Hom.: 14

Bravo AF: 0.0166

TwinsUK AF: 0.00 AC: 0

ALSPAC AF: 0.000519 AC: 2

ESP6500AA AF: 0.0486 AC: 193

ESP6500EA AF: 0.000120 AC: 1

ExAC AF: 0.00467 AC: 565

Asia WGS AF: 0.00260 AC: 9 AN: 3478

EpiCase AF: 0.0000545

EpiControl AF: 0.000119

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:26

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:8

-

Clinical Genetics, Academic Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Mar 12, 2013

Eurofins Ntd Llc (ga)

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 13, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 26, 2012

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. -

-

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

Significance: Benign

Review Status: no assertion criteria provided

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

- -

Oct 17, 2020

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

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Benign:5

-

Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Oct 31, 2024

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

- -

-

Genome Diagnostics Laboratory, University Medical Center Utrecht

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

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. -

Sep 10, 2021

Genome-Nilou Lab

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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. -

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. -

Tibial muscular dystrophy Benign:2

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. -

Sep 10, 2021

Genome-Nilou Lab

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

TTN-related disorder Benign:1

May 20, 2019

PreventionGenetics, part of Exact Sciences

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

This variant is classified as benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

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

May 16, 2023

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

Jul 08, 2015

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: 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

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.082
BayesDel_addAF	Benign	-0.45	T
BayesDel_noAF	Benign	-0.38
CADD	Benign	19
DANN	Benign	0.77
Eigen	Benign	-0.25
Eigen_PC	Benign	-0.078
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Benign	0.77	T;T;T;.;T;T;T
MetaRNN	Benign	0.0045	T;T;T;T;T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.94	.;.;.;L;.;.;L
PrimateAI	Uncertain	0.68	T
PROVEAN	Uncertain	-2.9	D;D;.;.;D;D;.
REVEL	Benign	0.19
Sift	Benign	0.29	T;T;.;.;T;T;.
Polyphen		0.0020	.;.;.;B;.;.;B
Vest4		0.43
MVP		0.41
MPC		0.11
ClinPred		0.017	T
GERP RS		4.1

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: rs744427; hg19: chr2-179435887;