rs150725992

Positions:

• chr2-178776550-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 1P and 1B. PP2 BP4

The NM_001267550.2(TTN):​c.5314A>G​(p.Ser1772Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000163 in 1,612,108 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). Synonymous variant affecting the same amino acid position (i.e. S1772S) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000085 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00017 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:9 B:1
• Conservation: PhyloP100: 7.89

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 Uncertain_significance. Variant got 0 ACMG points.

• PP2: Missense variant where missense usually causes diseases, TTN
• BP4: Computational evidence support a benign effect (MetaRNN=0.29948878).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2	c.5314A>G	p.Ser1772Gly	missense_variant	28/363	ENST00000589042.5
TTN	NM_133379.5	c.5314A>G	p.Ser1772Gly	missense_variant	28/46	ENST00000360870.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5	c.5314A>G	p.Ser1772Gly	missense_variant	28/363	5	NM_001267550.2	P1
TTN	ENST00000360870.10	c.5314A>G	p.Ser1772Gly	missense_variant	28/46	5	NM_133379.5
TTN-AS1	ENST00000659121.1	n.3977T>C		non_coding_transcript_exon_variant	12/13

Frequencies

GnomAD3 genomes AF: 0.0000854 AC: 13 AN: 152202 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000176

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000108 AC: 27 AN: 249842 Hom.: 0 AF XY: 0.0000962 AC XY: 13 AN XY: 135114

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000238

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000171 AC: 249 AN: 1459906 Hom.: 0 Cov.: 33 AF XY: 0.000172 AC XY: 125 AN XY: 726346

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.000220

Gnomad4 OTH exome AF: 0.0000662

GnomAD4 genome AF: 0.0000854 AC: 13 AN: 152202 Hom.: 0 Cov.: 33 AF XY: 0.0000673 AC XY: 5 AN XY: 74348

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000176

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000117 Hom.: 0

Bravo AF: 0.000110

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000465 AC: 4

ExAC AF: 0.000173 AC: 21

EpiCase AF: 0.000109

EpiControl AF: 0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:9 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:1 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Jan 18, 2024	- -
Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Aug 22, 2018	- -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Dec 09, 2011

The Ser1772Gly variant (TTN) has not been previously reported in the literature nor previously identified by our laboratory, but has been listed in dbSNP (rs150 725992) in 0.07% (5/7020) of Caucasian chromosomes from a clinical cohort that i ncluded individuals with heart disease. Serine (Ser) at position 1772 is highly conserved in evolutionarily distant species, increasing the likelihood that a ch ange may not be tolerated. Computational tools are mixed on the predicted impact to the protein (AlignGVGD = benign, SIFT = pathogenic), though the accuracy of these tools is unclear. Additional information is needed to assess the clinical significance of this variant. -

Autosomal recessive limb-girdle muscular dystrophy type 2J Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 15, 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, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 14, 2017

- -

Dilated cardiomyopathy 1G Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 15, 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, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Early-onset myopathy with fatal cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 15, 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, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

New York Genome Center

Nov 18, 2022

- -

Tibial muscular dystrophy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 15, 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, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Myopathy, myofibrillar, 9, with early respiratory failure Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 15, 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, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.29
BayesDel_addAF	Benign	-0.19	T
BayesDel_noAF	Benign	-0.22
CADD	Benign	22
DANN	Benign	0.90
Eigen	Pathogenic	0.75
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.97	D;D;D;.;D;D;D;D
M_CAP	Benign	0.028	D
MetaRNN	Benign	0.30	T;T;T;T;T;T;T;T
MetaSVM	Uncertain	0.23	D
MutationTaster	Benign	0.83	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.60	T
PROVEAN	Uncertain	-2.8	D;D;.;.;D;D;.;D
REVEL	Uncertain	0.46
Sift	Benign	0.086	T;D;.;.;D;T;.;D
Polyphen		1.0, 1.0	.;.;.;D;.;.;D;D
Vest4		0.40
MVP		0.34
MPC		0.44
ClinPred		0.21	T
GERP RS		5.0

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: rs150725992; hg19: chr2-179641277;