rs2303836

Positions:

• chr2-178593275-G-A

Variant summary

Our verdict is Benign. Variant got -18 ACMG points: 0P and 18B. BP4_Moderate BP6_Very_Strong BA1

The NM_001267550.2(TTN):​c.58933C>T​(p.Leu19645Leu) variant causes a synonymous change. The variant allele was found at a frequency of 0.0109 in 1,613,362 control chromosomes in the GnomAD database, including 1,485 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★).

• Frequency:
  • Genomes: 𝑓 0.015 (156 hom., cov: 32)
  • Exomes 𝑓: 0.010 (1329 hom.)
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Benign criteria provided, multiple submitters, no conflicts B:24
• Conservation: PhyloP100: 3.97

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:):

ACMG classification

Verdict is Benign. Variant got -18 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.41).
• BP6: Variant 2-178593275-G-A is Benign according to our data. Variant chr2-178593275-G-A is described in ClinVar as [Benign]. Clinvar id is 47142.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178593275-G-A is described in Lovd as [Benign]. Variant chr2-178593275-G-A is described in Lovd as [Likely_benign].
• BA1: GnomAd4 highest subpopulation (AMR) allele frequency at 95% confidence interval = 0.104 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2	c.58933C>T	p.Leu19645Leu	synonymous_variant	299/363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.58933C>T	p.Leu19645Leu	synonymous_variant	299/363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.0153 AC: 2324 AN: 152020 Hom.: 154 Cov.: 32

Gnomad AFR AF: 0.00287

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.108

Gnomad ASJ AF: 0.00144

Gnomad EAS AF: 0.0719

Gnomad SAS AF: 0.00580

Gnomad FIN AF: 0.00188

Gnomad MID AF: 0.00316

Gnomad NFE AF: 0.00146

Gnomad OTH AF: 0.0163

GnomAD3 exomes AF: 0.0378 AC: 9404 AN: 248544 Hom.: 1023 AF XY: 0.0293 AC XY: 3954 AN XY: 134820

Gnomad AFR exome AF: 0.00323

Gnomad AMR exome AF: 0.222

Gnomad ASJ exome AF: 0.000796

Gnomad EAS exome AF: 0.0659

Gnomad SAS exome AF: 0.00448

Gnomad FIN exome AF: 0.00209

Gnomad NFE exome AF: 0.00158

Gnomad OTH exome AF: 0.0290

GnomAD4 exome AF: 0.0104 AC: 15238 AN: 1461224 Hom.: 1329 Cov.: 35 AF XY: 0.00939 AC XY: 6824 AN XY: 726886

Gnomad4 AFR exome AF: 0.00242

Gnomad4 AMR exome AF: 0.207

Gnomad4 ASJ exome AF: 0.00111

Gnomad4 EAS exome AF: 0.0866

Gnomad4 SAS exome AF: 0.00492

Gnomad4 FIN exome AF: 0.00221

Gnomad4 NFE exome AF: 0.00114

Gnomad4 OTH exome AF: 0.0101

GnomAD4 genome AF: 0.0153 AC: 2335 AN: 152138 Hom.: 156 Cov.: 32 AF XY: 0.0163 AC XY: 1215 AN XY: 74362

Gnomad4 AFR AF: 0.00286

Gnomad4 AMR AF: 0.109

Gnomad4 ASJ AF: 0.00144

Gnomad4 EAS AF: 0.0721

Gnomad4 SAS AF: 0.00601

Gnomad4 FIN AF: 0.00188

Gnomad4 NFE AF: 0.00146

Gnomad4 OTH AF: 0.0161

Alfa AF: 0.0119 Hom.: 192

Bravo AF: 0.0275

Asia WGS AF: 0.0380 AC: 131 AN: 3476

EpiCase AF: 0.000709

EpiControl AF: 0.00119

ClinVar

Significance: Benign

Submissions summary: Benign:24

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:9

Benign, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Mar 04, 2013	- -
Benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Benign, criteria provided, single submitter	clinical testing	PreventionGenetics, part of Exact Sciences	-	- -
Benign, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Jul 30, 2012	- -
Likely benign, no assertion criteria provided	clinical testing	Genetic Services Laboratory, University of Chicago	-	Likely benign based on allele frequency in 1000 Genomes Project or ESP global frequency and its presence in a patient with a rare or unrelated disease phenotype. NOT Sanger confirmed. -
Benign, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Oct 08, 2013	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	-	- -
Benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Aug 19, 2019	- -

not provided Benign:3

Likely benign, no assertion criteria provided	clinical testing	Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)	-	- -
Benign, criteria provided, single submitter	clinical testing	Athena Diagnostics	May 30, 2019	- -
Benign, criteria provided, single submitter	not provided	Breakthrough Genomics, Breakthrough Genomics	-	- -

Autosomal recessive limb-girdle muscular dystrophy type 2J Benign:2

Benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 10, 2021	- -
Benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 13, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Early-onset myopathy with fatal cardiomyopathy Benign:2

Benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 10, 2021	- -
Benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 13, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Myopathy, myofibrillar, 9, with early respiratory failure Benign:2

Benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 10, 2021	- -
Benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 13, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Tibial muscular dystrophy Benign:2

Benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 10, 2021	- -
Benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 13, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

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

Benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 01, 2024

- -

Dilated cardiomyopathy 1G Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Cardiomyopathy Benign:1

Benign, criteria provided, single submitter

clinical testing

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Nov 19, 2015

- -

Cardiovascular phenotype Benign:1

Benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 31, 2013

This alteration is classified as benign based on a combination of the following: population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.41
CADD	Benign	1.8
DANN	Benign	0.84

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs2303836; hg19: chr2-179458002; COSMIC: COSV59948251; COSMIC: COSV59948251;