rs72647876

Positions:

• chr2-178777862-C-G
• chr2-178777862-C-T

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.4322G>C​(p.Arg1441Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00955 in 1,614,030 control chromosomes in the GnomAD database, including 92 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.0084 (10 hom., cov: 33)
  • Exomes 𝑓: 0.0097 (82 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:28
• Conservation: PhyloP100: 7.67

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]

LOC101927055 (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=0.008319944).
• BP6: Variant 2-178777862-C-G is Benign according to our data. Variant chr2-178777862-C-G is described in ClinVar as [Likely_benign]. Clinvar id is 47046.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178777862-C-G is described in Lovd as [Benign]. Variant chr2-178777862-C-G is described in Lovd as [Likely_benign].
• BS1: Variant frequency is greater than expected in population sas. gnomad4 allele frequency = 0.00843 (1284/152296) while in subpopulation SAS AF= 0.0162 (78/4828). AF 95% confidence interval is 0.0137. There are 10 homozygotes in gnomad4. There are 729 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.
• BS2: High Homozygotes in GnomAd4 at 10 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2	c.4322G>C	p.Arg1441Pro	missense_variant	25/363	ENST00000589042.5	NP_001254479.2
TTN	NM_133379.5	c.4322G>C	p.Arg1441Pro	missense_variant	25/46	ENST00000360870.10	NP_596870.2
LOC101927055	NR_120594.1	n.937C>G		non_coding_transcript_exon_variant	1/2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.4322G>C	p.Arg1441Pro	missense_variant	25/363	5	NM_001267550.2	ENSP00000467141	P1
TTN	ENST00000360870.10	c.4322G>C	p.Arg1441Pro	missense_variant	25/46	5	NM_133379.5	ENSP00000354117
TTN-AS1	ENST00000659121.1	n.5289C>G		non_coding_transcript_exon_variant	12/13

Frequencies

GnomAD3 genomes AF: 0.00845 AC: 1286 AN: 152178 Hom.: 11 Cov.: 33

Gnomad AFR AF: 0.00130

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0153

Gnomad ASJ AF: 0.00894

Gnomad EAS AF: 0.0104

Gnomad SAS AF: 0.0166

Gnomad FIN AF: 0.0200

Gnomad MID AF: 0.00633

Gnomad NFE AF: 0.00875

Gnomad OTH AF: 0.0115

GnomAD3 exomes AF: 0.0110 AC: 2754 AN: 250888 Hom.: 20 AF XY: 0.0117 AC XY: 1585 AN XY: 135572

Gnomad AFR exome AF: 0.00142

Gnomad AMR exome AF: 0.00764

Gnomad ASJ exome AF: 0.00765

Gnomad EAS exome AF: 0.00899

Gnomad SAS exome AF: 0.0169

Gnomad FIN exome AF: 0.0203

Gnomad NFE exome AF: 0.0105

Gnomad OTH exome AF: 0.0126

GnomAD4 exome AF: 0.00967 AC: 14137 AN: 1461734 Hom.: 82 Cov.: 34 AF XY: 0.0100 AC XY: 7275 AN XY: 727170

Gnomad4 AFR exome AF: 0.00137

Gnomad4 AMR exome AF: 0.00807

Gnomad4 ASJ exome AF: 0.00808

Gnomad4 EAS exome AF: 0.00423

Gnomad4 SAS exome AF: 0.0171

Gnomad4 FIN exome AF: 0.0183

Gnomad4 NFE exome AF: 0.00918

Gnomad4 OTH exome AF: 0.0102

GnomAD4 genome AF: 0.00843 AC: 1284 AN: 152296 Hom.: 10 Cov.: 33 AF XY: 0.00979 AC XY: 729 AN XY: 74476

Gnomad4 AFR AF: 0.00130

Gnomad4 AMR AF: 0.0153

Gnomad4 ASJ AF: 0.00894

Gnomad4 EAS AF: 0.0102

Gnomad4 SAS AF: 0.0162

Gnomad4 FIN AF: 0.0200

Gnomad4 NFE AF: 0.00875

Gnomad4 OTH AF: 0.0114

Alfa AF: 0.00752 Hom.: 3

Bravo AF: 0.00711

TwinsUK AF: 0.00998 AC: 37

ALSPAC AF: 0.00752 AC: 29

ESP6500AA AF: 0.00227 AC: 10

ESP6500EA AF: 0.00756 AC: 65

ExAC AF: 0.0111 AC: 1349

EpiCase AF: 0.00927

EpiControl AF: 0.0101

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:28

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:10

Likely benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jul 27, 2021	- -
Benign, criteria provided, single submitter	research	Biesecker Lab/Clinical Genomics Section, National Institutes of Health	Jun 24, 2013	- -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Jul 11, 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	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -
Benign, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -
Benign, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	May 10, 2012	Arg1441Pro in exon 25 of TTN: This variant is not expected to have clinical sign ificance because it is not located within the splice consensus sequence and has been identified in 0.6% (48/7020) of European American chromosomes by the NHLBI Exome sequencing project in a broad population (http://evs.gs.washington.edu/EVS , dbSNP rs72647876). -
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	Clinical Genetics, Academic Medical Center	-	- -
Benign, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Aug 05, 2015	- -
Benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -

not provided Benign:6

Likely benign, no assertion criteria provided	clinical testing	Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)	-	- -
Likely benign, criteria provided, single submitter	not provided	Breakthrough Genomics, Breakthrough Genomics	-	- -
Benign, criteria provided, single submitter	clinical testing	Athena Diagnostics	Jun 19, 2019	- -
Benign, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Nov 02, 2023	- -
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	Dec 01, 2022	TTN: BS1, BS2 -

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 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 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

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

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

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. -
Benign, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 10, 2021	- -

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

- -

Cardiomyopathy Benign:1

Benign, criteria provided, single submitter

clinical testing

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

Aug 03, 2017

- -

Dilated cardiomyopathy 1G Benign:1

Likely 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 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

Oct 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	Uncertain	0.52
BayesDel_addAF	Benign	-0.16	T
BayesDel_noAF	Uncertain	0.010
CADD	Uncertain	24
DANN	Benign	0.96
Eigen	Pathogenic	0.80
Eigen_PC	Pathogenic	0.80
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D;D;D;.;D;D;D;D
MetaRNN	Benign	0.0083	T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.40	T
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.75	T
PROVEAN	Uncertain	-4.2	D;D;.;.;D;D;.;D
REVEL	Uncertain	0.46
Sift	Benign	0.095	T;D;.;.;D;D;.;D
Sift4G	Uncertain	0.0050	.;.;.;.;.;.;.;D
Polyphen		1.0	.;.;.;D;.;.;D;D
Vest4		0.19
MPC		0.55
ClinPred		0.014	T
GERP RS		5.5

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: rs72647876; hg19: chr2-179642589;