chr2-178774365-T-A

Variant names:

• chr2-178774365-T-A
• rs772093035
• NM_001267550.2:c.6899A>T

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_001267550.2(TTN):​c.6899A>T​(p.Tyr2300Phe) variant causes a missense change. The variant allele was found at a frequency of 0.00000479 in 1,461,798 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y2300C) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.09
• 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]

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.19714376).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.6899A>T	p.Tyr2300Phe	missense_variant	Exon 30 of 363	ENST00000589042.5	NP_001254479.2
TTN	NM_133379.5	c.6899A>T	p.Tyr2300Phe	missense_variant	Exon 30 of 46	ENST00000360870.10	NP_596870.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.6899A>T	p.Tyr2300Phe	missense_variant	Exon 30 of 363	5	NM_001267550.2	ENSP00000467141.1
TTN	ENST00000360870.10	c.6899A>T	p.Tyr2300Phe	missense_variant	Exon 30 of 46	5	NM_133379.5	ENSP00000354117.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251046 AF XY: 0.00000737

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461798 Hom.: 0 Cov.: 33 AF XY: 0.00000550 AC XY: 4 AN XY: 727208

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.0000812 AC: 7 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53410

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111948

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Dec 07, 2022

Mayo Clinic Laboratories, Mayo Clinic

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

BP4, PM2 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.073
BayesDel_addAF	Benign	-0.16	T
BayesDel_noAF	Benign	-0.37
CADD	Benign	22
DANN	Benign	0.87
Eigen	Benign	0.054
Eigen_PC	Uncertain	0.23
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.92	D;D;D;.;D;D;D;D
M_CAP	Benign	0.013	T
MetaRNN	Benign	0.20	T;T;T;T;T;T;T;T
MetaSVM	Benign	-1.0	T
PhyloP100		5.1
PrimateAI	Uncertain	0.56	T
PROVEAN	Uncertain	-2.6	D;N;.;.;N;N;.;D
REVEL	Benign	0.17
Sift	Benign	0.32	T;T;.;.;T;T;.;T
Sift4G	Benign	0.39	.;.;.;.;.;.;.;T
Polyphen		0.22, 0.72	.;.;.;B;.;.;B;P
Vest4		0.42
MutPred		0.53		Loss of ubiquitination at K2298 (P = 0.0603);.;Loss of ubiquitination at K2298 (P = 0.0603);Loss of ubiquitination at K2298 (P = 0.0603);.;.;Loss of ubiquitination at K2298 (P = 0.0603);Loss of ubiquitination at K2298 (P = 0.0603);
MVP		0.24
MPC		0.086
ClinPred		0.15	T
GERP RS		5.6
Mutation Taster		=79/21	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: rs772093035; hg19: chr2-179639092;