rs758125069

Positions:

• chr2-178582216-AATTG-A

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 0P and 1B. BP6

The NM_001267550.2(TTN):​c.66161-12_66161-9del variant causes a splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000127 in 1,586,714 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000099 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00013 (0 hom.)
• Consequence: TTN NM_001267550.2 splice_polypyrimidine_tract, intron
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:2
• Conservation: PhyloP100: 2.60

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 -1 ACMG points.

• BP6: Variant 2-178582216-AATTG-A is Benign according to our data. Variant chr2-178582216-AATTG-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 413199.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=1, Likely_benign=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2	c.66161-12_66161-9del		splice_polypyrimidine_tract_variant, intron_variant		ENST00000589042.5
TTN-AS1	NR_038272.1	n.2044-350_2044-347del		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5	c.66161-12_66161-9del		splice_polypyrimidine_tract_variant, intron_variant		5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1	n.417-15374_417-15371del		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes AF: 0.0000987 AC: 15 AN: 152036 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000483

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: 0.0000942

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000176

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000773 AC: 17 AN: 220002 Hom.: 0 AF XY: 0.0000751 AC XY: 9 AN XY: 119830

Gnomad AFR exome AF: 0.000203

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000632

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.0000478

Gnomad NFE exome AF: 0.000115

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000130 AC: 187 AN: 1434678 Hom.: 0 AF XY: 0.000123 AC XY: 88 AN XY: 713058

Gnomad4 AFR exome AF: 0.0000638

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000254

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000188

Gnomad4 NFE exome AF: 0.000153

Gnomad4 OTH exome AF: 0.000236

GnomAD4 genome AF: 0.0000987 AC: 15 AN: 152036 Hom.: 0 Cov.: 32 AF XY: 0.0000808 AC XY: 6 AN XY: 74244

Gnomad4 AFR AF: 0.0000483

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.0000942

Gnomad4 NFE AF: 0.000176

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000793

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Jun 16, 2022

- -

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

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Jan 02, 2024

- -

not provided Benign:1

Likely benign, criteria provided, single submitter

clinical testing

GeneDx

May 29, 2018

- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.080		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: rs758125069; hg19: chr2-179446943;