chr2-178535209-G-C

Variant names:

• chr2-178535209-G-C
• rs55802460
• NM_001267550.2:c.101406C>G

Variant summary

Our verdict is Benign. The variant received -21 ACMG points: 0P and 21B. BP4_Strong BP6_Very_Strong BP7 BS1 BS2

The NM_001267550.2(TTN):​c.101406C>G​(p.Val33802Val) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00215 in 1,613,920 control chromosomes in the GnomAD database, including 52 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Synonymous variant affecting the same amino acid position (i.e. V33802V) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0018 (5 hom., cov: 32)
  • Exomes 𝑓: 0.0022 (47 hom.)
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:26
• Conservation: PhyloP100: 0.469
• Publications: 1 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: Benign. The variant received -21 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.5).
• BP6: Variant 2-178535209-G-C is Benign according to our data. Variant chr2-178535209-G-C is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 47638.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=0.469 with no splicing effect.
• BS1: Variant frequency is greater than expected in population sas. GnomAd4 allele frequency = 0.00175 (267/152284) while in subpopulation SAS AF = 0.0238 (115/4828). AF 95% confidence interval is 0.0203. There are 5 homozygotes in GnomAd4. There are 150 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.
• BS2: High Homozygotes in GnomAd4 at 5 AD,AR gene

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.101406C>G	p.Val33802Val	synonymous	Exon 358 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.96483C>G	p.Val32161Val	synonymous	Exon 308 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.93702C>G	p.Val31234Val	synonymous	Exon 307 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.101406C>G	p.Val33802Val	synonymous	Exon 358 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.101250C>G	p.Val33750Val	synonymous	Exon 356 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.101130C>G	p.Val33710Val	synonymous	Exon 356 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.00173 AC: 264 AN: 152166 Hom.: 4 Cov.: 32

Gnomad AFR AF: 0.000169

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00170

Gnomad ASJ AF: 0.000865

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.0232

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00166

Gnomad OTH AF: 0.00144

GnomAD2 exomes AF: 0.00369 AC: 918 AN: 248880 AF XY: 0.00470

Gnomad AFR exome AF: 0.000129

Gnomad AMR exome AF: 0.000782

Gnomad ASJ exome AF: 0.000895

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00172

Gnomad OTH exome AF: 0.00348

GnomAD4 exome AF: 0.00220 AC: 3210 AN: 1461636 Hom.: 47 Cov.: 38 AF XY: 0.00281 AC XY: 2046 AN XY: 727090

African (AFR) AF: 0.000329 AC: 11 AN: 33474

American (AMR) AF: 0.000693 AC: 31 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.000842 AC: 22 AN: 26134

East Asian (EAS) AF: 0.0000504 AC: 2 AN: 39698

South Asian (SAS) AF: 0.0210 AC: 1815 AN: 86254

European-Finnish (FIN) AF: 0.0000749 AC: 4 AN: 53382

Middle Eastern (MID) AF: 0.00433 AC: 25 AN: 5768

European-Non Finnish (NFE) AF: 0.00102 AC: 1136 AN: 1111834

Other (OTH) AF: 0.00272 AC: 164 AN: 60374

GnomAD4 genome AF: 0.00175 AC: 267 AN: 152284 Hom.: 5 Cov.: 32 AF XY: 0.00201 AC XY: 150 AN XY: 74462

African (AFR) AF: 0.000168 AC: 7 AN: 41570

American (AMR) AF: 0.00170 AC: 26 AN: 15284

Ashkenazi Jewish (ASJ) AF: 0.000865 AC: 3 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5176

South Asian (SAS) AF: 0.0238 AC: 115 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10618

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.00166 AC: 113 AN: 68022

Other (OTH) AF: 0.00142 AC: 3 AN: 2112

Alfa AF: 0.00132 Hom.: 0

Bravo AF: 0.00104

Asia WGS AF: 0.00953 AC: 33 AN: 3478

EpiCase AF: 0.00289

EpiControl AF: 0.00243

ClinVar

ClinVar submissions

Significance: Benign/Likely benign

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	-	8	not specified (8)
-	-	5	not provided (5)
-	-	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	Cardiomyopathy (1)
-	-	1	Cardiovascular phenotype (1)
-	-	1	Dilated cardiomyopathy 1G (1)
-	-	1	TTN-related disorder (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.50
CADD	Benign	0.046
DANN	Benign	0.72
PhyloP100		0.47
Mutation Taster		=93/7	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: rs55802460; hg19: chr2-179399936;