rs727504474

Variant names:

• chr2-178613083-A-G
• rs727504474
• NM_001267550.2:c.49649-11T>C

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4_Strong BP6

The NM_001267550.2(TTN):​c.49649-11T>C variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000465 in 1,612,246 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000046 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000047 (1 hom.)
• Consequence: TTN NM_001267550.2 intron
• Scores: Splicing: ADA: 0.0007421
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:4
• Conservation: PhyloP100: 0.652

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 Likely_benign. Variant got -5 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.83).
• BP6: Variant 2-178613083-A-G is Benign according to our data. Variant chr2-178613083-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 178830.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=2}. Variant chr2-178613083-A-G is described in Lovd as [Benign]. Variant chr2-178613083-A-G is described in Lovd as [Likely_benign].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.49649-11T>C		intron_variant	Intron 264 of 362	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.49649-11T>C		intron_variant	Intron 264 of 362	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.0000461 AC: 7 AN: 151972 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.000103

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000525 AC: 13 AN: 247552 Hom.: 0 AF XY: 0.0000745 AC XY: 10 AN XY: 134272

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000146

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: 0.0000714

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000466 AC: 68 AN: 1460274 Hom.: 1 Cov.: 33 AF XY: 0.0000523 AC XY: 38 AN XY: 726400

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000897

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: 0.0000558

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000461 AC: 7 AN: 151972 Hom.: 0 Cov.: 32 AF XY: 0.0000539 AC XY: 4 AN XY: 74208

Gnomad4 AFR AF: 0.00

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: 0.000103

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000693 Hom.: 0

Bravo AF: 0.0000529

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 Benign:4

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:1 Benign:2

-

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

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

- -

Apr 16, 2024

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Has not been previously published as pathogenic or benign to our knowledge; In silico analysis is inconclusive as to whether the variant alters gene splicing. In the absence of RNA/functional studies, the actual effect of this sequence change is unknown.; Located in the A-band region of TTN in which the majority of loss of function variants have been associated with autosomal dominant titinopathies (PMID: 22335739) -

not specified Uncertain:1 Benign:1

-

Clinical Genetics, Academic Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Apr 02, 2013

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The 41945-11T>C variant in TTN has been identified by our laboratory in 1 infant with DCM (LMM unpublished data). This variant has not been identified in large European American and African American populations by the NHLBI Exome Sequencing Project (http://evs.gs.washington.edu/EVS/), though it may be present in other populations. It is located in the 3' splice region. Computational tools do not s uggest an impact to splicing, though this information is not predictive enough t o rule out pathogenicity. Additional information is needed to fully assess the c linical significance of this variant. -

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

Jan 14, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.83
CADD	Benign	12
DANN	Benign	0.77
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00074
dbscSNV1_RF	Benign	0.054
SpliceAI score (max)		0.21		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.21		Position offset: -11

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

Publications

LitVar

Other links and lift over

dbSNP: rs727504474; hg19: chr2-179477810; COSMIC: COSV60286107; COSMIC: COSV60286107;