rs727504902

Variant names:

• chr2-178696179-G-A
• rs727504902
• NM_001267550.2:c.30893C>T

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_Strong

The NM_001267550.2(TTN):​c.30893C>T​(p.Ala10298Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000064 in 1,407,044 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000064 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.558
• 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]

LOC124906100 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -4 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.06131935).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.30893C>T	p.Ala10298Val	missense_variant	Exon 114 of 363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.30893C>T	p.Ala10298Val	missense_variant	Exon 114 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000581 AC: 1 AN: 172038 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000393

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: 0.00000640 AC: 9 AN: 1407044 Hom.: 0 Cov.: 31 AF XY: 0.00000720 AC XY: 5 AN XY: 694708

African (AFR) AF: 0.00 AC: 0 AN: 32176

American (AMR) AF: 0.0000276 AC: 1 AN: 36290

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25422

East Asian (EAS) AF: 0.00 AC: 0 AN: 37340

South Asian (SAS) AF: 0.00 AC: 0 AN: 79968

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 49600

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5704

European-Non Finnish (NFE) AF: 0.00000739 AC: 8 AN: 1082236

Other (OTH) AF: 0.00 AC: 0 AN: 58308

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Sep 05, 2018

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

proposed classification - variant undergoing re-assessment, contact laboratory -

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 08, 2021

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.093
BayesDel_addAF	Benign	-0.23	T
BayesDel_noAF	Benign	-0.45
CADD	Benign	16
DANN	Benign	0.69
DEOGEN2	Benign	0.086	.;.;.;.;T
Eigen	Benign	-0.61
Eigen_PC	Benign	-0.55
FATHMM_MKL	Benign	0.38	N
LIST_S2	Benign	0.67	T;T;.;T;T
M_CAP	Benign	0.021	T
MetaRNN	Benign	0.061	T;T;T;T;T
MetaSVM	Benign	-0.87	T
PhyloP100		0.56
PrimateAI	Benign	0.34	T
PROVEAN	Benign	-1.6	N;.;.;.;D
REVEL	Benign	0.047
Sift	Uncertain	0.023	D;.;.;.;T
Polyphen		0.0	.;.;B;B;.
Vest4		0.12
MutPred		0.26		.;.;Loss of helix (P = 0.0376);Loss of helix (P = 0.0376);.;
MVP		0.17
MPC		0.083
ClinPred		0.032	T
GERP RS		-0.017
Mutation Taster		=85/15	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: rs727504902; hg19: chr2-179560906;