rs376744914

chr2-178709675-C-T

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_Strong BP6 BP7

The NM_001267550.2(TTN):c.28644G>A(p.Thr9548=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00016 in 1,613,774 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 0.00020 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00016 (0 hom.)
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:6
• Conservation: PhyloP100: -2.10

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 Likely_benign. Variant got -6 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.72).
• BP6: Variant 2-178709675-C-T is Benign according to our data. Variant chr2-178709675-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 413174.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=4, Uncertain_significance=1}. Variant chr2-178709675-C-T is described in Lovd as [Benign]. Variant chr2-178709675-C-T is described in Lovd as [Likely_benign].
• BP7: Synonymous conserved (PhyloP=-2.1 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2	c.28644G>A	p.Thr9548=	synonymous_variant	99/363	ENST00000589042.5
LOC124906100	XR_007087318.1	n.2186-4079C>T		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5	c.28644G>A	p.Thr9548=	synonymous_variant	99/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1	n.503-24829C>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes AF: 0.000204 AC: 31 AN: 152166 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.000434

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.0000943

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000162

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000169 AC: 42 AN: 249190 Hom.: 0 AF XY: 0.000200 AC XY: 27 AN XY: 135190

Gnomad AFR exome AF: 0.000194

Gnomad AMR exome AF: 0.0000580

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000556

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000319

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000155 AC: 227 AN: 1461608 Hom.: 0 Cov.: 31 AF XY: 0.000158 AC XY: 115 AN XY: 727092

Gnomad4 AFR exome AF: 0.000358

Gnomad4 AMR exome AF: 0.0000671

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.0000187

Gnomad4 NFE exome AF: 0.000183

Gnomad4 OTH exome AF: 0.0000994

GnomAD4 genome AF: 0.000204 AC: 31 AN: 152166 Hom.: 0 Cov.: 33 AF XY: 0.000215 AC XY: 16 AN XY: 74324

Gnomad4 AFR AF: 0.000434

Gnomad4 AMR AF: 0.0000655

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.0000943

Gnomad4 NFE AF: 0.000162

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000142 Hom.: 0

Bravo AF: 0.000170

EpiCase AF: 0.000109

EpiControl AF: 0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:6

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:1 Benign:2

Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Oct 19, 2016	- -
Likely benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Likely benign, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Mar 01, 2021	- -

not specified Benign:3

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Mar 06, 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. -
Benign, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -
Likely benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Aug 16, 2019	- -

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

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Jan 24, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.72
Cadd	Benign	0.027
Dann	Benign	0.68

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: rs376744914; hg19: chr2-179574402;