2-178740039-T-C

Variant names:

• chr2-178740039-T-C
• rs375347596
• NM_001267550.2:c.13194A>G

Variant summary

Our verdict is Benign. The variant received -17 ACMG points: 0P and 17B. BP4_Strong BP6_Very_Strong BP7 BS1

The NM_001267550.2(TTN):​c.13194A>G​(p.Gln4398Gln) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000172 in 1,613,880 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.0010 (1 hom., cov: 32)
  • Exomes 𝑓: 0.000082 (0 hom.)
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:13
• Conservation: PhyloP100: 1.29
• Publications: 2 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 -17 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.6).
• BP6: Variant 2-178740039-T-C is Benign according to our data. Variant chr2-178740039-T-C is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 47834.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=1.29 with no splicing effect.
• BS1: Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.00103 (157/152274) while in subpopulation AFR AF = 0.00363 (151/41564). AF 95% confidence interval is 0.00316. There are 1 homozygotes in GnomAd4. There are 86 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

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.13194A>G	p.Gln4398Gln	synonymous	Exon 48 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.12243A>G	p.Gln4081Gln	synonymous	Exon 46 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133437.4		c.12681A>G	p.Gln4227Gln	synonymous	Exon 46 of 192	NP_597681.4	A0A0A0MRA3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	ENST00000589042.5	TSL:5 MANE Select	c.13194A>G	p.Gln4398Gln	synonymous	Exon 48 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.13194A>G	p.Gln4398Gln	synonymous	Exon 48 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.12918A>G	p.Gln4306Gln	synonymous	Exon 46 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.00101 AC: 153 AN: 152156 Hom.: 1 Cov.: 32

Gnomad AFR AF: 0.00355

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000327

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: 0.000478

GnomAD2 exomes AF: 0.000318 AC: 79 AN: 248346 AF XY: 0.000282

Gnomad AFR exome AF: 0.00465

Gnomad AMR exome AF: 0.000203

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000821 AC: 120 AN: 1461606 Hom.: 0 Cov.: 31 AF XY: 0.0000564 AC XY: 41 AN XY: 727078

African (AFR) AF: 0.00278 AC: 93 AN: 33478

American (AMR) AF: 0.000157 AC: 7 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26128

East Asian (EAS) AF: 0.00 AC: 0 AN: 39670

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53396

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

European-Non Finnish (NFE) AF: 0.00000540 AC: 6 AN: 1111826

Other (OTH) AF: 0.000215 AC: 13 AN: 60368

GnomAD4 genome AF: 0.00103 AC: 157 AN: 152274 Hom.: 1 Cov.: 32 AF XY: 0.00116 AC XY: 86 AN XY: 74448

African (AFR) AF: 0.00363 AC: 151 AN: 41564

American (AMR) AF: 0.000327 AC: 5 AN: 15290

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5178

South Asian (SAS) AF: 0.00 AC: 0 AN: 4818

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: 0.00 AC: 0 AN: 68014

Other (OTH) AF: 0.000473 AC: 1 AN: 2116

Alfa AF: 0.0000428 Hom.: 0

Bravo AF: 0.00122

Asia WGS AF: 0.000867 AC: 3 AN: 3476

ClinVar

ClinVar submissions as Germline

Significance: Benign/Likely benign

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	-	5	not specified (5)
-	-	2	not provided (2)
-	-	1	Autosomal recessive limb-girdle muscular dystrophy type 2J (1)
-	-	1	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G (1)
-	-	1	Cardiovascular phenotype (1)
-	-	1	Early-onset myopathy with fatal cardiomyopathy (1)
-	-	1	Myopathy, myofibrillar, 9, with early respiratory failure (1)
-	-	1	Tibial muscular dystrophy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.60
CADD	Benign	2.3
DANN	Benign	0.53
PhyloP100		1.3
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: rs375347596; hg19: chr2-179604766; COSMIC: COSV104643422; COSMIC: COSV104643422;