rs200675195

Variant names:

• chr2-178535237-T-A
• rs200675195
• NM_001267550.2:c.101378A>T

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 0P and 1B. BP4

The NM_001267550.2(TTN):​c.101378A>T​(p.Asp33793Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000177 in 1,613,854 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). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D33793N) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000085 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00019 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:10 B:2
• Conservation: PhyloP100: 8.02
• Publications: 3 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 -1 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.35315526).

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.101378A>T	p.Asp33793Val	missense	Exon 358 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.96455A>T	p.Asp32152Val	missense	Exon 308 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.93674A>T	p.Asp31225Val	missense	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.101378A>T	p.Asp33793Val	missense	Exon 358 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.101222A>T	p.Asp33741Val	missense	Exon 356 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.101102A>T	p.Asp33701Val	missense	Exon 356 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.0000854 AC: 13 AN: 152228 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

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: 0.0000883 AC: 22 AN: 249074 AF XY: 0.0000962

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: 0.000195

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000187 AC: 273 AN: 1461626 Hom.: 0 Cov.: 38 AF XY: 0.000166 AC XY: 121 AN XY: 727086

African (AFR) AF: 0.00 AC: 0 AN: 33470

American (AMR) AF: 0.0000447 AC: 2 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

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

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.000225 AC: 250 AN: 1111824

Other (OTH) AF: 0.000348 AC: 21 AN: 60374

GnomAD4 genome AF: 0.0000854 AC: 13 AN: 152228 Hom.: 0 Cov.: 33 AF XY: 0.000108 AC XY: 8 AN XY: 74378

African (AFR) AF: 0.0000241 AC: 1 AN: 41456

American (AMR) AF: 0.0000654 AC: 1 AN: 15282

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3466

East Asian (EAS) AF: 0.00 AC: 0 AN: 5196

South Asian (SAS) AF: 0.00 AC: 0 AN: 4838

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10630

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

European-Non Finnish (NFE) AF: 0.000162 AC: 11 AN: 68040

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.000227 Hom.: 0

Bravo AF: 0.000113

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000611 AC: 5

ExAC AF: 0.000116 AC: 14

EpiCase AF: 0.000436

EpiControl AF: 0.000237

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	3	1	not provided (4)
-	2	1	not specified (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	-	Cardiomyopathy (1)
-	1	-	Cardiovascular phenotype (1)
-	1	-	TTN-related disorder (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.79
BayesDel_addAF	Benign	-0.080	T
BayesDel_noAF	Uncertain	-0.080
CADD	Benign	19
DANN	Benign	0.90
Eigen	Uncertain	0.64
Eigen_PC	Pathogenic	0.69
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	D
M_CAP	Uncertain	0.15	D
MetaRNN	Benign	0.35	T
MetaSVM	Benign	-0.29	T
MutationAssessor	Benign	0.0	N
PhyloP100		8.0
PrimateAI	Uncertain	0.67	T
PROVEAN	Pathogenic	-6.4	D
REVEL	Uncertain	0.43
Sift	Uncertain	0.0010	D
Polyphen		1.0	D
Vest4		0.55
MVP		0.68
MPC		0.55
ClinPred		0.48	T
GERP RS		5.8
Mutation Taster		=42/58	disease causing

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: rs200675195; hg19: chr2-179399964;