chr2-178546040-C-T

Variant names:

• chr2-178546040-C-T
• rs752309744
• NM_001267550.2:c.95196G>A

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_Moderate BP6 BP7

The NM_001267550.2(TTN):​c.95196G>A​(p.Pro31732Pro) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000108 in 1,613,640 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). Synonymous variant affecting the same amino acid position (i.e. P31732P) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000099 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00011 (0 hom.)
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:10
• Conservation: PhyloP100: 0.706
• 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: Likely_benign. The variant received -4 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.25).
• BP6: Variant 2-178546040-C-T is Benign according to our data. Variant chr2-178546040-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 332722.
• BP7: Synonymous conserved (PhyloP=0.706 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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	NM_001267550.2	MANE Select	c.95196G>A	p.Pro31732Pro	synonymous	Exon 343 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.90273G>A	p.Pro30091Pro	synonymous	Exon 293 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.87492G>A	p.Pro29164Pro	synonymous	Exon 292 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.95196G>A	p.Pro31732Pro	synonymous	Exon 343 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.95040G>A	p.Pro31680Pro	synonymous	Exon 341 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.94920G>A	p.Pro31640Pro	synonymous	Exon 341 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.0000986 AC: 15 AN: 152192 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000965

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.000162

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000524 AC: 13 AN: 248116 AF XY: 0.0000743

Gnomad AFR exome AF: 0.0000646

Gnomad AMR exome AF: 0.0000871

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000168

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000446

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000109 AC: 160 AN: 1461448 Hom.: 0 Cov.: 33 AF XY: 0.0000977 AC XY: 71 AN XY: 727006

African (AFR) AF: 0.0000598 AC: 2 AN: 33468

American (AMR) AF: 0.0000671 AC: 3 AN: 44712

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

East Asian (EAS) AF: 0.000101 AC: 4 AN: 39654

South Asian (SAS) AF: 0.0000464 AC: 4 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53386

Middle Eastern (MID) AF: 0.000174 AC: 1 AN: 5762

European-Non Finnish (NFE) AF: 0.000126 AC: 140 AN: 1111728

Other (OTH) AF: 0.0000994 AC: 6 AN: 60362

GnomAD4 genome AF: 0.0000986 AC: 15 AN: 152192 Hom.: 0 Cov.: 33 AF XY: 0.0000673 AC XY: 5 AN XY: 74338

African (AFR) AF: 0.0000965 AC: 4 AN: 41456

American (AMR) AF: 0.00 AC: 0 AN: 15276

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5194

South Asian (SAS) AF: 0.00 AC: 0 AN: 4834

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10616

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

European-Non Finnish (NFE) AF: 0.000162 AC: 11 AN: 68032

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

Alfa AF: 0.000135 Hom.: 0

Bravo AF: 0.0000945

EpiCase AF: 0.000164

EpiControl AF: 0.000119

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	-	4	not provided (4)
-	-	2	not specified (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	-	Dilated cardiomyopathy 1G (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	-0.25
CADD	Benign	0.64
DANN	Benign	0.87
PhyloP100		0.71
Mutation Taster		=90/10	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: rs752309744; hg19: chr2-179410767; COSMIC: COSV59941000; COSMIC: COSV59941000;