rs376744914

Variant names:

• chr2-178709675-C-T
• rs376744914
• NM_001267550.2:c.28644G>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.28644G>A​(p.Thr9548Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00016 in 1,613,774 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 0.00020 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00016 (0 hom.)
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:7
• Conservation: PhyloP100: -2.10
• 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 -6 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.72).
• BP6: Variant 2-178709675-C-T is Benign according to our data. Variant chr2-178709675-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 413174.
• BP7: Synonymous conserved (PhyloP=-2.1 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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	NM_001267550.2	MANE Select	c.28644G>A	p.Thr9548Thr	synonymous	Exon 99 of 363	NP_001254479.2
	TTN	NM_001256850.1		c.27693G>A	p.Thr9231Thr	synonymous	Exon 97 of 313	NP_001243779.1
	TTN	NM_133378.4		c.24912G>A	p.Thr8304Thr	synonymous	Exon 96 of 312	NP_596869.4

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	ENST00000589042.5	TSL:5 MANE Select	c.28644G>A	p.Thr9548Thr	synonymous	Exon 99 of 363	ENSP00000467141.1
	TTN	ENST00000446966.2	TSL:1	c.28644G>A	p.Thr9548Thr	synonymous	Exon 99 of 361	ENSP00000408004.2
	TTN	ENST00000436599.2	TSL:1	c.28368G>A	p.Thr9456Thr	synonymous	Exon 97 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes AF: 0.000204 AC: 31 AN: 152166 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.000434

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.0000943

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000162

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.000169 AC: 42 AN: 249190 AF XY: 0.000200

Gnomad AFR exome AF: 0.000194

Gnomad AMR exome AF: 0.0000580

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000556

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000319

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000155 AC: 227 AN: 1461608 Hom.: 0 Cov.: 31 AF XY: 0.000158 AC XY: 115 AN XY: 727092

African (AFR) AF: 0.000358 AC: 12 AN: 33474

American (AMR) AF: 0.0000671 AC: 3 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86256

European-Finnish (FIN) AF: 0.0000187 AC: 1 AN: 53398

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.000183 AC: 204 AN: 1111802

Other (OTH) AF: 0.0000994 AC: 6 AN: 60370

GnomAD4 genome AF: 0.000204 AC: 31 AN: 152166 Hom.: 0 Cov.: 33 AF XY: 0.000215 AC XY: 16 AN XY: 74324

African (AFR) AF: 0.000434 AC: 18 AN: 41440

American (AMR) AF: 0.0000655 AC: 1 AN: 15274

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5192

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

European-Finnish (FIN) AF: 0.0000943 AC: 1 AN: 10610

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

European-Non Finnish (NFE) AF: 0.000162 AC: 11 AN: 68036

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

Alfa AF: 0.000142 Hom.: 0

Bravo AF: 0.000170

EpiCase AF: 0.000109

EpiControl AF: 0.000119

ClinVar

ClinVar submissions as Germline

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

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

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.72
CADD	Benign	0.027
DANN	Benign	0.68
PhyloP100		-2.1
Mutation Taster		=100/0	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: rs376744914; hg19: chr2-179574402;