2-178685560-G-C

Position:

• chr2-178685560-G-C

Variant summary

Our verdict is Benign. Variant got -19 ACMG points: 1P and 20B. PP2 BP4_Strong BP6_Very_Strong BS1 BS2

The NM_001267550.2(TTN):​c.32350C>G​(p.Leu10784Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00144 in 1,613,652 control chromosomes in the GnomAD database, including 13 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/17 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.0043 (6 hom., cov: 32)
  • Exomes 𝑓: 0.0011 (7 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:25
• Conservation: PhyloP100: 0.206

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 -19 ACMG points.

• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), TTN. . Gene score misZ -1.1021 (greater than the threshold 3.09). Trascript score misZ 6.9794 (greater than threshold 3.09). GenCC has associacion of gene with dilated cardiomyopathy, tibial muscular dystrophy, early-onset myopathy with fatal cardiomyopathy, autosomal recessive centronuclear myopathy, hypertrophic cardiomyopathy, hypertrophic cardiomyopathy 9, TTN-related myopathy, dilated cardiomyopathy 1G, arrhythmogenic right ventricular cardiomyopathy, myopathy, myofibrillar, 9, with early respiratory failure, familial isolated dilated cardiomyopathy, childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndrome, autosomal recessive limb-girdle muscular dystrophy type 2J.
• BP4: Computational evidence support a benign effect (MetaRNN=0.0038782358).
• BP6: Variant 2-178685560-G-C is Benign according to our data. Variant chr2-178685560-G-C is described in ClinVar as [Likely_benign]. Clinvar id is 46864.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178685560-G-C is described in Lovd as [Benign]. Variant chr2-178685560-G-C is described in Lovd as [Likely_benign].
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00427 (651/152284) while in subpopulation AFR AF= 0.0118 (491/41546). AF 95% confidence interval is 0.011. There are 6 homozygotes in gnomad4. There are 319 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.
• BS2: High Homozygotes in GnomAd4 at 6 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2	c.32350C>G	p.Leu10784Val	missense_variant	128/363	ENST00000589042.5	NP_001254479.2
LOC124906100	XR_007087318.1	n.2186-28194G>C		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.32350C>G	p.Leu10784Val	missense_variant	128/363	5	NM_001267550.2	ENSP00000467141	P1
TTN-AS1	ENST00000659121.1	n.503-48944G>C		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes AF: 0.00428 AC: 652 AN: 152164 Hom.: 6 Cov.: 32

Gnomad AFR AF: 0.0119

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00406

Gnomad ASJ AF: 0.0153

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00633

Gnomad NFE AF: 0.000529

Gnomad OTH AF: 0.00382

GnomAD3 exomes AF: 0.00207 AC: 515 AN: 248616 Hom.: 2 AF XY: 0.00192 AC XY: 259 AN XY: 134888

Gnomad AFR exome AF: 0.0118

Gnomad AMR exome AF: 0.00189

Gnomad ASJ exome AF: 0.0171

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.000262

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000622

Gnomad OTH exome AF: 0.00282

GnomAD4 exome AF: 0.00114 AC: 1672 AN: 1461368 Hom.: 7 Cov.: 31 AF XY: 0.00115 AC XY: 838 AN XY: 726924

Gnomad4 AFR exome AF: 0.0121

Gnomad4 AMR exome AF: 0.00195

Gnomad4 ASJ exome AF: 0.0170

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.000244

Gnomad4 FIN exome AF: 0.0000187

Gnomad4 NFE exome AF: 0.000440

Gnomad4 OTH exome AF: 0.00292

GnomAD4 genome AF: 0.00427 AC: 651 AN: 152284 Hom.: 6 Cov.: 32 AF XY: 0.00428 AC XY: 319 AN XY: 74462

Gnomad4 AFR AF: 0.0118

Gnomad4 AMR AF: 0.00405

Gnomad4 ASJ AF: 0.0153

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000529

Gnomad4 OTH AF: 0.00378

Alfa AF: 0.00216 Hom.: 1

Bravo AF: 0.00525

ESP6500AA AF: 0.00973 AC: 37

ESP6500EA AF: 0.00134 AC: 11

ExAC AF: 0.00189 AC: 229

Asia WGS AF: 0.000867 AC: 3 AN: 3474

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:25

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:9

Benign, criteria provided, single submitter	research	Biesecker Lab/Clinical Genomics Section, National Institutes of Health	Jun 24, 2013	- -
Benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Benign, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -
Benign, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -
Likely benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Mar 10, 2020	- -
Benign, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Sep 02, 2016	- -
Benign, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Nov 10, 2015	- -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Apr 26, 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, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Apr 06, 2015	p.Leu9540Val in exon 125 of TTN: This variant is not expected to have clinical s ignificance because it has been identified in 1.2% of African chromosomes by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP rs726 50029). -

not provided Benign:4

Likely benign, no assertion criteria provided	clinical testing	Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen	-	- -
Benign, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Aug 01, 2024	TTN: BP4, BS1, BS2 -
Likely benign, criteria provided, single submitter	not provided	Breakthrough Genomics, Breakthrough Genomics	-	- -
Likely benign, no assertion criteria provided	clinical testing	Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)	-	- -

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

Benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 10, 2021	- -
Likely benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Early-onset myopathy with fatal cardiomyopathy Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -
Benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 10, 2021	- -

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 12, 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 12, 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

Jan 31, 2024

- -

Cardiomyopathy Benign:1

Benign, criteria provided, single submitter

clinical testing

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

Aug 11, 2016

- -

Dilated cardiomyopathy 1G Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Cardiovascular phenotype Benign:1

Benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 12, 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
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.54	T
BayesDel_noAF	Benign	-0.54
CADD	Benign	13
DANN	Benign	0.94
Eigen	Benign	-0.78
Eigen_PC	Benign	-0.60
FATHMM_MKL	Benign	0.045	N
LIST_S2	Benign	0.42	T;T;.;T
MetaRNN	Benign	0.0039	T;T;T;T
MetaSVM	Benign	-1.0	T
MutationTaster	Benign	1.0	N;N;N;N;N;N
PrimateAI	Benign	0.40	T
PROVEAN	Benign	-0.85	N;.;.;.
REVEL	Benign	0.16
Sift	Benign	1.0	T;.;.;.
Polyphen		0.0	.;.;B;B
Vest4		0.24
MVP		0.18
MPC		0.084
ClinPred		0.0030	T
GERP RS		2.0

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: rs72650029; hg19: chr2-179550287;