rs370135800

Variant names:

• chr2-178553007-T-C
• rs370135800
• NM_001267550.2:c.89893A>G

Variant summary

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

The NM_001267550.2(TTN):​c.89893A>G​(p.Ile29965Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000434 in 1,611,684 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000026 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.91
• 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=0.096957356).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.89893A>G	p.Ile29965Val	missense_variant	Exon 335 of 363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.89893A>G	p.Ile29965Val	missense_variant	Exon 335 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152208 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000965

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.0000122 AC: 3 AN: 246756 AF XY: 0.0000149

Gnomad AFR exome AF: 0.0000646

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000112

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1459476 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 726132

African (AFR) AF: 0.0000299 AC: 1 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44712

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

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39626

South Asian (SAS) AF: 0.00 AC: 0 AN: 86246

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111756

Other (OTH) AF: 0.0000166 AC: 1 AN: 60348

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152208 Hom.: 0 Cov.: 33 AF XY: 0.0000403 AC XY: 3 AN XY: 74352

African (AFR) AF: 0.0000965 AC: 4 AN: 41464

American (AMR) AF: 0.00 AC: 0 AN: 15272

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5200

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10626

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68028

Other (OTH) AF: 0.00 AC: 0 AN: 2088

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.0000189

ESP6500AA AF: 0.000265 AC: 1

ESP6500EA AF: 0.00 AC: 0

ExAC AF: 0.0000248 AC: 3

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Dec 08, 2016

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant classified as Uncertain Significance - Favor Benign. The p.Ile27397Val v ariant in TTN has not been previously reported in individuals with cardiomyopath y, but has been identified in 2/9770 African chromosomes by the Exome Aggregatio n Consortium (ExAC, http://exac.broadinstitute.org; dbSNP rs370135800). Isoleuci ne (Ile) at position 27397 is not conserved in mammals or evolutionarily distant species, and 17 species (including 2 mammals) carry a valine (Val) at this posi tion, supporting that this change may be tolerated. Additional computational pre diction tools suggest that the p.Ile27397Val variant may not impact the protein, though this information is not predictive enough to rule out pathogenicity. In summary, while the clinical significance of the p.Ile27397Val variant is uncerta in, these data suggest that it is more likely to be benign. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.069
BayesDel_addAF	Benign	-0.30	T
BayesDel_noAF	Benign	-0.45
CADD	Benign	13
DANN	Benign	0.94
Eigen	Benign	-0.11
Eigen_PC	Benign	0.095
FATHMM_MKL	Benign	0.69	D
LIST_S2	Uncertain	0.86	D;D;D;.;D;D;T
M_CAP	Benign	0.022	T
MetaRNN	Benign	0.097	T;T;T;T;T;T;T
MetaSVM	Benign	-0.96	T
MutationAssessor	Benign	0.12	.;.;.;N;.;.;N
PhyloP100		1.9
PrimateAI	Benign	0.39	T
PROVEAN	Benign	-0.73	N;N;.;.;N;N;.
REVEL	Benign	0.079
Sift	Benign	0.20	T;T;.;.;T;T;.
Polyphen		0.0040	.;.;.;B;.;.;B
Vest4		0.19
MVP		0.43
MPC		0.072
ClinPred		0.045	T
GERP RS		5.7
Mutation Taster		=99/1	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: rs370135800; hg19: chr2-179417734;