NM_001267550.2:c.74895A>C

Variant names:

• chr2-178571237-T-G
• rs201512527
• NM_001267550.2:c.74895A>C

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_Strong BP6 BS2

The NM_001267550.2(TTN):​c.74895A>C​(p.Gln24965His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000906 in 1,613,534 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. 15/19 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 0.00081 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00092 (3 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4 B:17
• Conservation: PhyloP100: 0.578

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 -9 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.0070705414).
• BP6: Variant 2-178571237-T-G is Benign according to our data. Variant chr2-178571237-T-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 47332.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=5, Benign=6, Uncertain_significance=4}. Variant chr2-178571237-T-G is described in Lovd as [Benign]. Variant chr2-178571237-T-G is described in Lovd as [Likely_benign].
• BS2: High Homozygotes in GnomAdExome4 at 3 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.74895A>C	p.Gln24965His	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.74895A>C	p.Gln24965His	missense_variant	Exon 326 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.000815 AC: 124 AN: 152094 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.000121

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000590

Gnomad ASJ AF: 0.0179

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000632

Gnomad OTH AF: 0.00239

GnomAD3 exomes AF: 0.00106 AC: 263 AN: 248454 Hom.: 1 AF XY: 0.00113 AC XY: 152 AN XY: 134760

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000754

Gnomad ASJ exome AF: 0.0162

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000596

Gnomad OTH exome AF: 0.00116

GnomAD4 exome AF: 0.000916 AC: 1338 AN: 1461322 Hom.: 3 Cov.: 40 AF XY: 0.000957 AC XY: 696 AN XY: 726958

Gnomad4 AFR exome AF: 0.0000897

Gnomad4 AMR exome AF: 0.000850

Gnomad4 ASJ exome AF: 0.0166

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.000679

Gnomad4 OTH exome AF: 0.00179

GnomAD4 genome AF: 0.000815 AC: 124 AN: 152212 Hom.: 0 Cov.: 33 AF XY: 0.000712 AC XY: 53 AN XY: 74402

Gnomad4 AFR AF: 0.000120

Gnomad4 AMR AF: 0.000590

Gnomad4 ASJ AF: 0.0179

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000632

Gnomad4 OTH AF: 0.00237

Alfa AF: 0.00130 Hom.: 2

Bravo AF: 0.000945

TwinsUK AF: 0.000539 AC: 2

ALSPAC AF: 0.000259 AC: 1

ESP6500AA AF: 0.000262 AC: 1

ESP6500EA AF: 0.00194 AC: 16

ExAC AF: 0.000985 AC: 119

EpiCase AF: 0.000709

EpiControl AF: 0.000652

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4 Benign:17

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Benign:7

-

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

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Mar 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

TTN: BP4, BS1 -

-

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

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

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

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Nov 21, 2019

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 01, 2020

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is associated with the following publications: (PMID: 23396983, 23861362, 27930701) -

Sep 14, 2018

Athena Diagnostics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not specified Benign:5

-

Clinical Genetics, Academic Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jun 09, 2015

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

p.Gln22397His in exon 275 of TTN This variant is not expected to have clinical s ignificance due to a lack of conservation across species, including mammals. Of note, 3 mammals (guinea pig, horse, and white rhinoceros) have a histidine (His) at this position despite high nearby amino acid conservation. In addition, the variant has been identified in 0.16% (107/66688) of European chromosomes by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP rs2015 12527). -

Aug 31, 2020

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

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: TTN c.67191A>C (p.Gln22397His) results in a non-conservative amino acid change located in the A-band of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.0011 in 248454 control chromosomes in the gnomAD database, including 1 homozygotes. The observed variant frequency is approximately 3 fold of the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Dilated Cardiomyopathy phenotype (0.00039), strongly suggesting that the variant is benign. To our knowledge, no occurrence of c.67191A>C in individuals affected with Dilated Cardiomyopathy and no experimental evidence demonstrating its impact on protein function have been reported. Ten clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Multiple laboratories reported the variant with conflicting assessments (benign/likely benign n=8, VUS n=2). Based on the evidence outlined above, the variant was classified as benign. -

Jun 24, 2015

Eurofins Ntd Llc (ga)

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

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

Jan 13, 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. -

Dilated cardiomyopathy 1G Uncertain:1

Jan 13, 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. -

Cardiomyopathy Uncertain:1

May 27, 2016

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

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Early-onset myopathy with fatal cardiomyopathy Uncertain:1

Jan 13, 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. -

TTN-related disorder Benign:1

Jun 29, 2020

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

Jan 31, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Tibial muscular dystrophy Benign:1

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:1

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. -

Cardiovascular phenotype Benign:1

Feb 12, 2018

Ambry Genetics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

General population or subpopulation frequency is too high to be a pathogenic mutation based on disease/syndrome prevalence and penetrance -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.46	T
BayesDel_noAF	Benign	-0.53
CADD	Benign	14
DANN	Benign	0.66
Eigen	Benign	-0.52
Eigen_PC	Benign	-0.41
FATHMM_MKL	Benign	0.65	D
LIST_S2	Benign	0.80	T;T;T;.;T;T;T
M_CAP	Benign	0.011	T
MetaRNN	Benign	0.0071	T;T;T;T;T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.55	.;.;.;N;.;.;N
PrimateAI	Benign	0.39	T
PROVEAN	Uncertain	-2.9	D;D;.;.;D;D;.
REVEL	Benign	0.066
Sift	Uncertain	0.028	D;D;.;.;D;D;.
Polyphen		0.0	.;.;.;B;.;.;B
Vest4		0.15
MutPred		0.38		.;.;.;Gain of catalytic residue at I23322 (P = 0.0877);.;.;Gain of catalytic residue at I23322 (P = 0.0877);
MVP		0.13
MPC		0.079
ClinPred		0.039	T
GERP RS		-2.0

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: rs201512527; hg19: chr2-179435964;