2-178752043-GAAAAA-GAAAAAAAAAAAAAAAAAA

Variant names:

• chr2-178752043-G-GAAAAAAAAAAAAA
• rs58651353
• NM_001267550.2:c.11311+1068_11311+1080dupTTTTTTTTTTTTT

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 0P and 0B.

The NM_001267550.2(TTN):​c.11311+1068_11311+1080dupTTTTTTTTTTTTT variant causes a intron change involving the alteration of a non-conserved nucleotide. It is difficult to determine the true allele frequency of this variant because it is of type INS_BIG, and the frequency of such variant types in population databases may be underestimated and unreliable. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: 𝑓 0.0000071 (0 hom., cov: 0)
• Consequence: TTN NM_001267550.2 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.56
• Publications: 5 publications found

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

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.11311+1068_11311+1080dupTTTTTTTTTTTTT		intron_variant	Intron 47 of 362	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.11311+1080_11311+1081insTTTTTTTTTTTTT		intron_variant	Intron 47 of 362	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.00000710 AC: 1 AN: 140938 Hom.: 0 Cov.: 0

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: 0.0000155

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 0

GnomAD4 genome AF: 0.00000710 AC: 1 AN: 140938 Hom.: 0 Cov.: 0 AF XY: 0.0000147 AC XY: 1 AN XY: 68190

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 38332

American (AMR) AF: 0.00 AC: 0 AN: 14032

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3308

East Asian (EAS) AF: 0.00 AC: 0 AN: 4888

South Asian (SAS) AF: 0.00 AC: 0 AN: 4486

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 8348

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 304

European-Non Finnish (NFE) AF: 0.0000155 AC: 1 AN: 64446

Other (OTH) AF: 0.00 AC: 0 AN: 1914

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		2.6

Splicing

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

Other links and lift over

dbSNP: rs58651353; hg19: chr2-179616770;