rs370684491

Variant names:

• chr2-178729722-C-G
• rs370684491
• NM_001267550.2:c.18531G>C

Variant summary

Our verdict is Benign. The variant received -15 ACMG points: 0P and 15B. BP4_Moderate BP6_Very_Strong BP7 BS1

The NM_001267550.2(TTN):​c.18531G>C​(p.Val6177Val) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000144 in 1,613,782 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 Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.00084 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000072 (0 hom.)
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:12
• Conservation: PhyloP100: 2.91
• 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 -15 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.44).
• BP6: Variant 2-178729722-C-G is Benign according to our data. Variant chr2-178729722-C-G is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 46639.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=2.91 with no splicing effect.
• BS1: Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.000841 (128/152274) while in subpopulation AFR AF = 0.00298 (124/41584). AF 95% confidence interval is 0.00255. There are 0 homozygotes in GnomAd4. There are 64 alleles in the male GnomAd4 subpopulation. Median coverage is 33. 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.18531G>C	p.Val6177Val	synonymous	Exon 63 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.17580G>C	p.Val5860Val	synonymous	Exon 61 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.14799G>C	p.Val4933Val	synonymous	Exon 60 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.18531G>C	p.Val6177Val	synonymous	Exon 63 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.18531G>C	p.Val6177Val	synonymous	Exon 63 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.18255G>C	p.Val6085Val	synonymous	Exon 61 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.000815 AC: 124 AN: 152156 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00289

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000196

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: 0.000254 AC: 63 AN: 248492 AF XY: 0.000200

Gnomad AFR exome AF: 0.00388

Gnomad AMR exome AF: 0.0000869

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: 0.0000718 AC: 105 AN: 1461508 Hom.: 0 Cov.: 33 AF XY: 0.0000468 AC XY: 34 AN XY: 727036

African (AFR) AF: 0.00248 AC: 83 AN: 33460

American (AMR) AF: 0.0000894 AC: 4 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26124

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53402

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

European-Non Finnish (NFE) AF: 0.00000450 AC: 5 AN: 1111732

Other (OTH) AF: 0.000215 AC: 13 AN: 60362

GnomAD4 genome AF: 0.000841 AC: 128 AN: 152274 Hom.: 0 Cov.: 33 AF XY: 0.000860 AC XY: 64 AN XY: 74446

African (AFR) AF: 0.00298 AC: 124 AN: 41584

American (AMR) AF: 0.000196 AC: 3 AN: 15290

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5164

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10622

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 67996

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

Alfa AF: 0.000363 Hom.: 0

Bravo AF: 0.000994

Asia WGS AF: 0.000866 AC: 3 AN: 3478

ClinVar

ClinVar submissions

Significance: Benign/Likely benign

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	-	6	not specified (6)
-	-	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	Early-onset myopathy with fatal cardiomyopathy (1)
-	-	1	Myopathy, myofibrillar, 9, with early respiratory failure (1)
-	-	1	not provided (1)
-	-	1	Tibial muscular dystrophy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.44
CADD	Benign	5.0
DANN	Benign	0.72
PhyloP100		2.9
Mutation Taster		=22/78	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs370684491; hg19: chr2-179594449;