2-178647040-GTATATATATA-GTATATATATATATATATATATA

Variant names:

• chr2-178647040-G-GTATATATATATA
• rs10580462
• NM_001267550.2:c.40222+12_40222+23dupTATATATATATA

Variant summary

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

The NM_001267550.2(TTN):​c.40222+12_40222+23dupTATATATATATA variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000138 in 731,440 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 0.00037 (0 hom., cov: 21)
  • Exomes 𝑓: 0.000082 (0 hom.)
• Consequence: TTN NM_001267550.2 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.212
• Publications: 4 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]

LOC124906100 (HGNC:):

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.40222+12_40222+23dupTATATATATATA		intron_variant	Intron 215 of 362	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.40222+23_40222+24insTATATATATATA		intron_variant	Intron 215 of 362	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.000370 AC: 53 AN: 143282 Hom.: 0 Cov.: 21

Gnomad AFR AF: 0.000126

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000908

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00143

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.000578

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000324

Gnomad OTH AF: 0.00103

GnomAD4 exome AF: 0.0000816 AC: 48 AN: 588092 Hom.: 0 Cov.: 0 AF XY: 0.0000923 AC XY: 27 AN XY: 292396

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

African (AFR) AF: 0.00 AC: 0 AN: 12696

American (AMR) AF: 0.000138 AC: 1 AN: 7260

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 9790

East Asian (EAS) AF: 0.000104 AC: 2 AN: 19322

South Asian (SAS) AF: 0.00 AC: 0 AN: 10496

European-Finnish (FIN) AF: 0.000285 AC: 8 AN: 28092

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 1866

European-Non Finnish (NFE) AF: 0.0000739 AC: 35 AN: 473392

Other (OTH) AF: 0.0000794 AC: 2 AN: 25178

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome AF: 0.000370 AC: 53 AN: 143348 Hom.: 0 Cov.: 21 AF XY: 0.000345 AC XY: 24 AN XY: 69550

African (AFR) AF: 0.000126 AC: 5 AN: 39728

American (AMR) AF: 0.000907 AC: 13 AN: 14328

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3374

East Asian (EAS) AF: 0.00144 AC: 7 AN: 4870

South Asian (SAS) AF: 0.00 AC: 0 AN: 4444

European-Finnish (FIN) AF: 0.000578 AC: 5 AN: 8656

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 270

European-Non Finnish (NFE) AF: 0.000324 AC: 21 AN: 64840

Other (OTH) AF: 0.00102 AC: 2 AN: 1958

Alfa AF: 0.00 Hom.: 16

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		-0.21

Splicing

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

Other links and lift over

dbSNP: rs10580462; hg19: chr2-179511767;