rs1553860465

Variant names:

• chr2-178693949-G-C
• rs1553860465
• NM_001267550.2:c.31486C>G

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001267550.2(TTN):​c.31486C>G​(p.His10496Asp) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 11/19 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)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 4.32
• 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]

LOC124907912 (HGNC:):

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: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.24420094).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.31486C>G	p.His10496Asp	missense_variant	Exon 118 of 363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.31486C>G	p.His10496Asp	missense_variant	Exon 118 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:2

Jan 04, 2018

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The TTN c.27754C>G; p.His9252Asp variant, to our knowledge, is not reported in the medical literature, gene specific variation databases, nor has it been previously identified by our laboratory. This variant is absent from the general population databases (1000 Genomes Project, Exome Variant Server, Genome Aggregation Database), indicating it is not a common polymorphism. The histidine at position 9252 is moderately conserved, considering 10 species, and computational analyses of the effects of the p.His9252Asp variant on protein structure and function make conflicting predictions (SIFT: tolerated, MutationTaster: disease causing, AlignGVGD: Class C0). Given the available evidence, the clinical significance of the p.His9252Asp variant cannot be determined with certainty.

Nov 13, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); Missense variant in a gene in which most reported pathogenic variants are truncating/loss of function; Has not been previously published as pathogenic or benign to our knowledge

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

Oct 30, 2017

Labcorp Genetics (formerly Invitae), Labcorp

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	Uncertain	0.38
BayesDel_addAF	Benign	-0.044	T
BayesDel_noAF	Benign	-0.30
CADD	Benign	21
DANN	Uncertain	0.99
DEOGEN2	Benign	0.0	.;.;.;.;T
Eigen	Benign	0.0037
Eigen_PC	Benign	0.20
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Benign	0.49	T;T;.;T;T
M_CAP	Benign	0.028	D
MetaRNN	Benign	0.24	T;T;T;T;T
MetaSVM	Benign	-0.77	T
MutationAssessor	Benign	0.0	.;.;.;.;.
PhyloP100		4.3
PrimateAI	Uncertain	0.63	T
PROVEAN	Uncertain	-4.0	D;.;.;.;D
REVEL	Benign	0.18
Sift	Uncertain	0.028	D;.;.;.;D
Sift4G	Pathogenic	0.0	.;.;.;.;.
Vest4		0.48
ClinPred		0.69	D
GERP RS		5.3
Mutation Taster		=91/9	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: rs1553860465; hg19: chr2-179558676;