rs397517655

Variant names:

• chr2-178587251-A-T
• rs397517655
• NM_001267550.2:c.63960T>A

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 0P and 6B. BP4_Strong BP6 BP7

The NM_001267550.2(TTN):​c.63960T>A​(p.Val21320Val) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000106 in 1,613,080 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000086 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00011 (0 hom.)
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:10
• Conservation: PhyloP100: 0.0340
• 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 -6 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.49).
• BP6: Variant 2-178587251-A-T is Benign according to our data. Variant chr2-178587251-A-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 47203.
• BP7: Synonymous conserved (PhyloP=0.034 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001267550.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	NM_001267550.2	MANE Select	c.63960T>A	p.Val21320Val	synonymous	Exon 307 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.59037T>A	p.Val19679Val	synonymous	Exon 257 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.56256T>A	p.Val18752Val	synonymous	Exon 256 of 312	NP_596869.4	Q8WZ42-11

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	ENST00000589042.5	TSL:5 MANE Select	c.63960T>A	p.Val21320Val	synonymous	Exon 307 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.63804T>A	p.Val21268Val	synonymous	Exon 305 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.63684T>A	p.Val21228Val	synonymous	Exon 305 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.0000855 AC: 13 AN: 152006 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000197

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: 0.000147

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000443 AC: 11 AN: 248194 AF XY: 0.0000297

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000116

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000624

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000108 AC: 158 AN: 1461074 Hom.: 0 Cov.: 33 AF XY: 0.0000949 AC XY: 69 AN XY: 726850

African (AFR) AF: 0.0000299 AC: 1 AN: 33430

American (AMR) AF: 0.0000671 AC: 3 AN: 44694

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26118

East Asian (EAS) AF: 0.00 AC: 0 AN: 39584

South Asian (SAS) AF: 0.00 AC: 0 AN: 86248

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53398

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.000130 AC: 145 AN: 1111508

Other (OTH) AF: 0.000149 AC: 9 AN: 60332

GnomAD4 genome AF: 0.0000855 AC: 13 AN: 152006 Hom.: 0 Cov.: 32 AF XY: 0.0000808 AC XY: 6 AN XY: 74218

African (AFR) AF: 0.00 AC: 0 AN: 41422

American (AMR) AF: 0.000197 AC: 3 AN: 15250

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5144

South Asian (SAS) AF: 0.00 AC: 0 AN: 4820

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: 0.000147 AC: 10 AN: 67966

Other (OTH) AF: 0.00 AC: 0 AN: 2086

Alfa AF: 0.000113 Hom.: 0

Bravo AF: 0.0000982

EpiCase AF: 0.0000545

EpiControl AF: 0.000119

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	1	4	not provided (5)
-	-	3	not specified (3)
-	-	1	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G (1)
-	-	1	Cardiomyopathy (1)
-	-	1	Cardiovascular phenotype (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.49
CADD	Benign	0.33
DANN	Benign	0.80
PhyloP100		0.034
Mutation Taster		=90/10	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: rs397517655; hg19: chr2-179451978;