2-178546041-G-A

Variant names:

• chr2-178546041-G-A
• rs753334568
• NM_001267550.2:c.95195C>T

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM1 PP3_Moderate PP5_Very_Strong

The NM_001267550.2(TTN):​c.95195C>T​(p.Pro31732Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000093 in 1,613,628 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. P31732P) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000089 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:15 O:1
• Conservation: PhyloP100: 10.0
• Publications: 15 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: Pathogenic. The variant received 12 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_001267550.2
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.845
• PP5: Variant 2-178546041-G-A is Pathogenic according to our data. Variant chr2-178546041-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 132137.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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.95195C>T	p.Pro31732Leu	missense	Exon 343 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.90272C>T	p.Pro30091Leu	missense	Exon 293 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.87491C>T	p.Pro29164Leu	missense	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.95195C>T	p.Pro31732Leu	missense	Exon 343 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.95039C>T	p.Pro31680Leu	missense	Exon 341 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.94919C>T	p.Pro31640Leu	missense	Exon 341 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152164 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.0000294

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000121 AC: 3 AN: 248136 AF XY: 0.00000743

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000178

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000890 AC: 13 AN: 1461464 Hom.: 0 Cov.: 33 AF XY: 0.00000550 AC XY: 4 AN XY: 727020

African (AFR) AF: 0.00 AC: 0 AN: 33468

American (AMR) AF: 0.0000224 AC: 1 AN: 44710

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39648

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86254

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

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

European-Non Finnish (NFE) AF: 0.00000899 AC: 10 AN: 1111744

Other (OTH) AF: 0.0000166 AC: 1 AN: 60362

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152164 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74334

African (AFR) AF: 0.00 AC: 0 AN: 41438

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

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5186

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

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: 0.0000294 AC: 2 AN: 68026

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

Alfa AF: 0.0000170 Hom.: 0

Bravo AF: 0.00000756

ExAC AF: 0.0000165 AC: 2

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
7	-	-	not provided (7)
2	-	-	Myopathy, myofibrillar, 9, with early respiratory failure (3)
1	-	-	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy (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	-	-	Hereditary inclusion-body myopathy (1)
1	-	-	Primary familial dilated cardiomyopathy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Pathogenic	0.14
CADD	Uncertain	23
DANN	Uncertain	0.98
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D
M_CAP	Pathogenic	0.34	D
MetaRNN	Pathogenic	0.84	D
MetaSVM	Pathogenic	0.89	D
MutationAssessor	Pathogenic	4.3	H
PhyloP100		10
PrimateAI	Uncertain	0.70	T
PROVEAN	Pathogenic	-7.5	D
REVEL	Pathogenic	0.73
Sift	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.58
MutPred		0.79		Loss of disorder (P = 0.085)
MVP		0.91
MPC		0.47
ClinPred		0.99	D
GERP RS		5.8
Mutation Taster		=2/98	disease causing (ClinVar)

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: rs753334568; hg19: chr2-179410768; COSMIC: COSV59865628; COSMIC: COSV59865628;