rs756679529

Variant names:

• chr2-178557045-T-C
• rs756679529
• NM_001267550.2:c.88109A>G

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PP3

The NM_001267550.2(TTN):​c.88109A>G​(p.Tyr29370Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000868 in 1,613,700 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 8.02
• Publications: 0 publications found

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]

ENSG00000279598 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PP3: MetaRNN computational evidence supports a deleterious effect, 0.81

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001267550.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	NM_001267550.2	MANE Select	c.88109A>G	p.Tyr29370Cys	missense	Exon 330 of 363	NP_001254479.2
	TTN	NM_001256850.1		c.83186A>G	p.Tyr27729Cys	missense	Exon 280 of 313	NP_001243779.1
	TTN	NM_133378.4		c.80405A>G	p.Tyr26802Cys	missense	Exon 279 of 312	NP_596869.4

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	ENST00000589042.5	TSL:5 MANE Select	c.88109A>G	p.Tyr29370Cys	missense	Exon 330 of 363	ENSP00000467141.1
	TTN	ENST00000446966.2	TSL:1	c.87953A>G	p.Tyr29318Cys	missense	Exon 328 of 361	ENSP00000408004.2
	TTN	ENST00000436599.2	TSL:1	c.87833A>G	p.Tyr29278Cys	missense	Exon 328 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152212 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000131

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: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000443 AC: 11 AN: 248484 AF XY: 0.0000371

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000319

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000821 AC: 12 AN: 1461488 Hom.: 0 Cov.: 33 AF XY: 0.00000688 AC XY: 5 AN XY: 727032

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.000268 AC: 12 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39596

South Asian (SAS) AF: 0.00 AC: 0 AN: 86248

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53382

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111802

Other (OTH) AF: 0.00 AC: 0 AN: 60366

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152212 Hom.: 0 Cov.: 33 AF XY: 0.0000135 AC XY: 1 AN XY: 74348

African (AFR) AF: 0.00 AC: 0 AN: 41458

American (AMR) AF: 0.000131 AC: 2 AN: 15274

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5196

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10622

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68042

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000340

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

Nov 14, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 Uncertain:1

Sep 14, 2021

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

not provided Uncertain:1

May 02, 2017

Eurofins Ntd Llc (ga)

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.86
BayesDel_addAF	Uncertain	0.079	D
BayesDel_noAF	Pathogenic	0.18
CADD	Benign	21
DANN	Benign	0.93
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Benign	0.074	D
MetaRNN	Pathogenic	0.81	D
MetaSVM	Uncertain	0.71	D
MutationAssessor	Pathogenic	4.4	H
PhyloP100		8.0
PrimateAI	Uncertain	0.77	T
PROVEAN	Pathogenic	-6.3	D
REVEL	Pathogenic	0.72
Sift	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.55
MutPred		0.88		Loss of phosphorylation at Y27729 (P = 0.0583)
MVP		0.82
MPC		0.50
ClinPred		0.43	T
GERP RS		5.9
Mutation Taster		=60/40	polymorphism

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

Other links and lift over

dbSNP: rs756679529; hg19: chr2-179421772;