rs2291308

Variant names:

• chr2-178779433-T-C
• rs2291308
• NM_001267550.2:c.3759A>G

Variant summary

Our verdict is Benign. The variant received -21 ACMG points: 0P and 21B. BP4_Strong BP6_Very_Strong BP7 BA1

The NM_001267550.2(TTN):​c.3759A>G​(p.Arg1253Arg) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0516 in 1,563,290 control chromosomes in the GnomAD database, including 3,615 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★).

• Frequency:
  • Genomes: 𝑓 0.050 (362 hom., cov: 33)
  • Exomes 𝑓: 0.052 (3253 hom.)
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Benign criteria provided, multiple submitters, no conflicts B:22
• Conservation: PhyloP100: -0.221
• Publications: 11 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]

LOC101927055 (HGNC:):

ACMG classification

Our verdict: Benign. The variant received -21 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.53).
• BP6: Variant 2-178779433-T-C is Benign according to our data. Variant chr2-178779433-T-C is described in ClinVar as Benign. ClinVar VariationId is 46985.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=-0.221 with no splicing effect.
• BA1: GnomAd4 highest subpopulation (EAS) allele frequency at 95% confidence interval = 0.175 is higher than 0.05.

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.3759A>G	p.Arg1253Arg	synonymous	Exon 23 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.3759A>G	p.Arg1253Arg	synonymous	Exon 23 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.3759A>G	p.Arg1253Arg	synonymous	Exon 23 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.3759A>G	p.Arg1253Arg	synonymous	Exon 23 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.3759A>G	p.Arg1253Arg	synonymous	Exon 23 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.3483A>G	p.Arg1161Arg	synonymous	Exon 21 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.0498 AC: 7581 AN: 152156 Hom.: 361 Cov.: 33

Gnomad AFR AF: 0.0117

Gnomad AMI AF: 0.0482

Gnomad AMR AF: 0.138

Gnomad ASJ AF: 0.0490

Gnomad EAS AF: 0.185

Gnomad SAS AF: 0.0218

Gnomad FIN AF: 0.0512

Gnomad MID AF: 0.0158

Gnomad NFE AF: 0.0452

Gnomad OTH AF: 0.0463

GnomAD2 exomes AF: 0.0797 AC: 19065 AN: 239316 AF XY: 0.0700

Gnomad AFR exome AF: 0.0109

Gnomad AMR exome AF: 0.239

Gnomad ASJ exome AF: 0.0485

Gnomad EAS exome AF: 0.203

Gnomad FIN exome AF: 0.0523

Gnomad NFE exome AF: 0.0442

Gnomad OTH exome AF: 0.0662

GnomAD4 exome AF: 0.0518 AC: 73061 AN: 1411016 Hom.: 3253 Cov.: 29 AF XY: 0.0500 AC XY: 35199 AN XY: 704326

African (AFR) AF: 0.00920 AC: 296 AN: 32190

American (AMR) AF: 0.227 AC: 9985 AN: 44016

Ashkenazi Jewish (ASJ) AF: 0.0471 AC: 1211 AN: 25732

East Asian (EAS) AF: 0.189 AC: 7362 AN: 38946

South Asian (SAS) AF: 0.0196 AC: 1646 AN: 84076

European-Finnish (FIN) AF: 0.0546 AC: 2890 AN: 52956

Middle Eastern (MID) AF: 0.0164 AC: 89 AN: 5436

European-Non Finnish (NFE) AF: 0.0436 AC: 46629 AN: 1069160

Other (OTH) AF: 0.0505 AC: 2953 AN: 58504

GnomAD4 genome AF: 0.0498 AC: 7584 AN: 152274 Hom.: 362 Cov.: 33 AF XY: 0.0514 AC XY: 3825 AN XY: 74452

African (AFR) AF: 0.0116 AC: 484 AN: 41574

American (AMR) AF: 0.138 AC: 2108 AN: 15280

Ashkenazi Jewish (ASJ) AF: 0.0490 AC: 170 AN: 3468

East Asian (EAS) AF: 0.185 AC: 957 AN: 5180

South Asian (SAS) AF: 0.0212 AC: 102 AN: 4820

European-Finnish (FIN) AF: 0.0512 AC: 543 AN: 10612

Middle Eastern (MID) AF: 0.0170 AC: 5 AN: 294

European-Non Finnish (NFE) AF: 0.0452 AC: 3076 AN: 68018

Other (OTH) AF: 0.0449 AC: 95 AN: 2116

Alfa AF: 0.0498 Hom.: 464

Bravo AF: 0.0608

Asia WGS AF: 0.0740 AC: 256 AN: 3472

ClinVar

ClinVar submissions

Significance: Benign

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	-	10	not specified (10)
-	-	2	Autosomal recessive limb-girdle muscular dystrophy type 2J (2)
-	-	2	Early-onset myopathy with fatal cardiomyopathy (2)
-	-	2	Myopathy, myofibrillar, 9, with early respiratory failure (2)
-	-	2	Tibial muscular dystrophy (2)
-	-	1	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G (1)
-	-	1	Cardiovascular phenotype (1)
-	-	1	Dilated cardiomyopathy 1G (1)
-	-	1	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.53
CADD	Benign	4.4
DANN	Benign	0.71
PhyloP100		-0.22
Mutation Taster		=89/11	polymorphism (auto)

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: rs2291308; hg19: chr2-179644160;