rs200284932

chr2-178751783-A-G

Variant summary

Our verdict is Benign. Variant got -15 ACMG points: 0P and 15B. BP4_Moderate BP6_Very_Strong BP7 BS2

The NM_133379.5(TTN):c.10617T>C(p.His3539=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000438 in 1,613,206 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.00041 (1 hom., cov: 32)
  • Exomes 𝑓: 0.00044 (2 hom.)
• Consequence: TTN NM_133379.5 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:8
• Conservation: PhyloP100: 2.20

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 Benign. Variant got -15 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.38).
• BP6: Variant 2-178751783-A-G is Benign according to our data. Variant chr2-178751783-A-G is described in ClinVar as [Likely_benign]. Clinvar id is 47728.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178751783-A-G is described in Lovd as [Likely_benign]. Variant chr2-178751783-A-G is described in Lovd as [Benign].
• BP7: Synonymous conserved (PhyloP=2.2 with no splicing effect.
• BS2: High Homozygotes in GnomAdExome at 2 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_133379.5	c.10617T>C	p.His3539=	synonymous_variant	46/46	ENST00000360870.10
TTN	NM_001267550.2	c.11311+1341T>C		intron_variant		ENST00000589042.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000360870.10	c.10617T>C	p.His3539=	synonymous_variant	46/46	5	NM_133379.5
TTN	ENST00000589042.5	c.11311+1341T>C		intron_variant		5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1	n.1224-4483A>G		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes AF: 0.000414 AC: 63 AN: 152000 Hom.: 1 Cov.: 32

Gnomad AFR AF: 0.0000724

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.0153

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000736

Gnomad OTH AF: 0.000959

GnomAD3 exomes AF: 0.000795 AC: 199 AN: 250208 Hom.: 2 AF XY: 0.000754 AC XY: 102 AN XY: 135226

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.0169

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000177

Gnomad OTH exome AF: 0.00164

GnomAD4 exome AF: 0.000441 AC: 644 AN: 1461088 Hom.: 2 Cov.: 39 AF XY: 0.000473 AC XY: 344 AN XY: 726830

Gnomad4 AFR exome AF: 0.000508

Gnomad4 AMR exome AF: 0.0000672

Gnomad4 ASJ exome AF: 0.0169

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000954

Gnomad4 OTH exome AF: 0.00121

GnomAD4 genome AF: 0.000414 AC: 63 AN: 152118 Hom.: 1 Cov.: 32 AF XY: 0.000403 AC XY: 30 AN XY: 74358

Gnomad4 AFR AF: 0.0000722

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.0153

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000736

Gnomad4 OTH AF: 0.000949

Alfa AF: 0.000989 Hom.: 0

Bravo AF: 0.000570

Asia WGS AF: 0.000577 AC: 2 AN: 3478

EpiCase AF: 0.000437

EpiControl AF: 0.000415

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:8

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:4

Benign, criteria provided, single submitter	clinical testing	GeneDx	Aug 27, 2015	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. -
Likely benign, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Jul 24, 2012	His3539His in exon 45A of TTN: This variant is not expected to have clinical sig nificance because it does not alter an amino acid residue and is not located wit hin the splice consensus sequence. It has been identified in 0.1% (6/7020) of Eu ropean American chromosomes from a broad population by the NHLBI Exome Sequencin g Project (http://evs.gs.washington.edu/EVS). His3539His in exon 45A of TTN (al lele frequency = 0.1%, 6/7020) ** -
Likely benign, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Mar 23, 2017	- -
Benign, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -

not provided Benign:2

Likely benign, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Mar 01, 2024	TTN: BP4, BP7 -
Likely benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -

TTN-related disorder Benign:1

Benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Feb 20, 2024

This variant is classified as benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Aug 18, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.38
Cadd	Benign	16
Dann	Benign	0.70

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: rs200284932; hg19: chr2-179616510;