rs201614524

Variant names:

• chr2-178584738-G-A
• rs201614524
• NM_001267550.2:c.64903C>T

Variant summary

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

The NM_001267550.2(TTN):​c.64903C>T​(p.Arg21635Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000018 in 1,613,344 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R21635H) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000046 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000015 (1 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5 B:1
• Conservation: PhyloP100: 9.94
• 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: Likely_benign. The variant received -1 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.3977202).

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.64903C>T	p.Arg21635Cys	missense	Exon 310 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.59980C>T	p.Arg19994Cys	missense	Exon 260 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.57199C>T	p.Arg19067Cys	missense	Exon 259 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.64903C>T	p.Arg21635Cys	missense	Exon 310 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.64747C>T	p.Arg21583Cys	missense	Exon 308 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.64627C>T	p.Arg21543Cys	missense	Exon 308 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.0000460 AC: 7 AN: 152046 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000483

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000388

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: 0.0000604 AC: 15 AN: 248496 AF XY: 0.0000519

Gnomad AFR exome AF: 0.0000646

Gnomad AMR exome AF: 0.0000290

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000167

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000890

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000151 AC: 22 AN: 1461298 Hom.: 1 Cov.: 32 AF XY: 0.0000138 AC XY: 10 AN XY: 726920

African (AFR) AF: 0.0000897 AC: 3 AN: 33446

American (AMR) AF: 0.0000224 AC: 1 AN: 44712

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26118

East Asian (EAS) AF: 0.0000504 AC: 2 AN: 39682

South Asian (SAS) AF: 0.00 AC: 0 AN: 86234

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: 0.0000144 AC: 16 AN: 1111598

Other (OTH) AF: 0.00 AC: 0 AN: 60344

GnomAD4 genome AF: 0.0000460 AC: 7 AN: 152046 Hom.: 0 Cov.: 32 AF XY: 0.0000539 AC XY: 4 AN XY: 74228

African (AFR) AF: 0.0000483 AC: 2 AN: 41438

American (AMR) AF: 0.0000655 AC: 1 AN: 15256

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

East Asian (EAS) AF: 0.000388 AC: 2 AN: 5156

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10600

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

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 67978

Other (OTH) AF: 0.00 AC: 0 AN: 2088

Alfa AF: 0.000108 Hom.: 0

Bravo AF: 0.0000793

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000243 AC: 2

ExAC AF: 0.0000248 AC: 3

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	2	1	not provided (3)
-	2	-	not specified (2)
-	1	-	Myopathy, myofibrillar, 9, with early respiratory failure (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.22
BayesDel_addAF	Benign	-0.061	T
BayesDel_noAF	Uncertain	-0.060
CADD	Uncertain	24
DANN	Uncertain	0.98
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.97	D
M_CAP	Benign	0.0083	T
MetaRNN	Benign	0.40	T
MetaSVM	Uncertain	-0.16	T
MutationAssessor	Benign	1.5	L
PhyloP100		9.9
PrimateAI	Uncertain	0.71	T
PROVEAN	Pathogenic	-5.5	D
REVEL	Uncertain	0.55
Sift	Uncertain	0.0090	D
Polyphen		1.0	D
Vest4		0.56
MVP		0.74
MPC		0.54
ClinPred		0.35	T
GERP RS		6.2
Mutation Taster		=92/8	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: rs201614524; hg19: chr2-179449465; COSMIC: COSV106105398; COSMIC: COSV106105398;