chr2-178590781-C-A

Variant names:

• chr2-178590781-C-A
• rs765839032
• NM_001267550.2:c.60944G>T

Variant summary

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

The NM_001267550.2(TTN):​c.60944G>T​(p.Gly20315Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000871 in 1,606,708 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G20315D) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000076 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.86
• 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: Uncertain_significance. The variant received 0 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.60944G>T	p.Gly20315Val	missense_variant	Exon 304 of 363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.60944G>T	p.Gly20315Val	missense_variant	Exon 304 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152052 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000656

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: 0.0000294

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000756 AC: 11 AN: 1454656 Hom.: 0 Cov.: 35 AF XY: 0.0000125 AC XY: 9 AN XY: 722240

African (AFR) AF: 0.0000300 AC: 1 AN: 33332

American (AMR) AF: 0.00 AC: 0 AN: 44514

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25942

East Asian (EAS) AF: 0.00 AC: 0 AN: 39454

South Asian (SAS) AF: 0.00 AC: 0 AN: 85796

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53236

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5734

European-Non Finnish (NFE) AF: 0.00000813 AC: 9 AN: 1106622

Other (OTH) AF: 0.0000167 AC: 1 AN: 60026

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152052 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74268

African (AFR) AF: 0.00 AC: 0 AN: 41432

American (AMR) AF: 0.0000656 AC: 1 AN: 15250

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5158

South Asian (SAS) AF: 0.00 AC: 0 AN: 4824

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

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

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 67980

Other (OTH) AF: 0.00 AC: 0 AN: 2090

Alfa AF: 0.0000283 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.74
BayesDel_addAF	Uncertain	0.11	D
BayesDel_noAF	Uncertain	-0.080
CADD	Benign	22
DANN	Benign	0.89
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D;D;.;D;D;D
M_CAP	Benign	0.0070	T
MetaRNN	Uncertain	0.44	T;T;T;T;T;T;T
MetaSVM	Benign	-0.46	T
MutationAssessor	Uncertain	2.8	.;.;.;M;.;.;M
PhyloP100		7.9
PrimateAI	Uncertain	0.64	T
PROVEAN	Pathogenic	-6.7	D;D;.;.;D;D;.
REVEL	Uncertain	0.41
Sift	Uncertain	0.029	D;T;.;.;T;D;.
Polyphen		1.0	.;.;.;D;.;.;D
Vest4		0.51
MutPred		0.60		.;.;.;Gain of methylation at K18675 (P = 0.0391);.;.;Gain of methylation at K18675 (P = 0.0391);
MVP		0.72
MPC		0.52
ClinPred		0.40	T
GERP RS		6.1
Mutation Taster		=52/48	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: rs765839032; hg19: chr2-179455508;