2-178663006-C-T

Variant summary

Our verdict is Benign. Variant got -13 ACMG points: 0P and 13B. BP4_Strong BP6_Very_Strong BP7

The NM_001267550.2(TTN):c.36750G>A(p.Pro12250=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.0013 (0 hom., cov: 26)
  • Exomes 𝑓: 0.00013 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:3
• Conservation: PhyloP100: -3.16

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

Verdict is Benign. Variant got -13 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.79).
• BP6: Variant 2-178663006-C-T is Benign according to our data. Variant chr2-178663006-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 380400.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178663006-C-T is described in Lovd as [Benign].
• BP7: Synonymous conserved (PhyloP=-3.16 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2	c.36750G>A	p.Pro12250=	synonymous_variant	174/363	ENST00000589042.5
LOC124906100	XR_007087318.1	n.2185+18505C>T		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5	c.36750G>A	p.Pro12250=	synonymous_variant	174/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1	n.502+65325C>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes AF: 0.00127 AC: 190 AN: 149832 Hom.: 0 Cov.: 26

Gnomad AFR AF: 0.00450

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000266

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000214

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000297

Gnomad OTH AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.000127 AC: 185 AN: 1458134 Hom.: 0 Cov.: 31 AF XY: 0.000101 AC XY: 73 AN XY: 725352

Gnomad4 AFR exome AF: 0.00367

Gnomad4 AMR exome AF: 0.000202

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000333

Gnomad4 OTH exome AF: 0.000250

GnomAD4 genome Data not reliable, filtered out with message: AS_VQSR AF: 0.00127 AC: 190 AN: 149932 Hom.: 0 Cov.: 26 AF XY: 0.00115 AC XY: 84 AN XY: 73092

Gnomad4 AFR AF: 0.00449

Gnomad4 AMR AF: 0.000265

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000214

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000297

Gnomad4 OTH AF: 0.00

ClinVar

Significance: Likely benign

Submissions summary: Benign:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jun 13, 2020	- -
Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Oct 16, 2017	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

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

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Nov 27, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.79
Cadd	Benign	1.5
Dann	Benign	0.83

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: rs777458053; hg19: chr2-179527733;