rs377141765

Variant names:

• chr2-178612448-C-T
• rs377141765
• NM_001267550.2:c.50077G>A

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_001267550.2(TTN):​c.50077G>A​(p.Val16693Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000353 in 1,612,486 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/20 in silico tools predict 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. V16693V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000033 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000036 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6 B:1
• Conservation: PhyloP100: 7.86
• 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 -2 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.12533918).

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.50077G>A	p.Val16693Ile	missense	Exon 266 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.45154G>A	p.Val15052Ile	missense	Exon 216 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.42373G>A	p.Val14125Ile	missense	Exon 215 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.50077G>A	p.Val16693Ile	missense	Exon 266 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.49921G>A	p.Val16641Ile	missense	Exon 264 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.49801G>A	p.Val16601Ile	missense	Exon 264 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.0000329 AC: 5 AN: 151936 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000656

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000442

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000203 AC: 5 AN: 246106 AF XY: 0.0000150

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.000100

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000271

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000356 AC: 52 AN: 1460432 Hom.: 0 Cov.: 33 AF XY: 0.0000385 AC XY: 28 AN XY: 726504

African (AFR) AF: 0.00 AC: 0 AN: 33406

American (AMR) AF: 0.0000224 AC: 1 AN: 44644

Ashkenazi Jewish (ASJ) AF: 0.0000383 AC: 1 AN: 26106

East Asian (EAS) AF: 0.00 AC: 0 AN: 39440

South Asian (SAS) AF: 0.00 AC: 0 AN: 86216

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53294

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5758

European-Non Finnish (NFE) AF: 0.0000450 AC: 50 AN: 1111282

Other (OTH) AF: 0.00 AC: 0 AN: 60286

GnomAD4 genome AF: 0.0000329 AC: 5 AN: 152054 Hom.: 0 Cov.: 33 AF XY: 0.0000135 AC XY: 1 AN XY: 74324

African (AFR) AF: 0.00 AC: 0 AN: 41546

American (AMR) AF: 0.0000655 AC: 1 AN: 15268

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5114

South Asian (SAS) AF: 0.000207 AC: 1 AN: 4822

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10610

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 292

European-Non Finnish (NFE) AF: 0.0000442 AC: 3 AN: 67908

Other (OTH) AF: 0.00 AC: 0 AN: 2112

Alfa AF: 0.0000282 Hom.: 0

Bravo AF: 0.0000151

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000121 AC: 1

ExAC AF: 0.0000166 AC: 2

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	3	1	not provided (4)
-	1	-	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G (1)
-	1	-	Cardiovascular phenotype (1)
-	1	-	not specified (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.17	T
BayesDel_noAF	Benign	-0.37
CADD	Benign	23
DANN	Benign	0.92
Eigen	Uncertain	0.36
Eigen_PC	Uncertain	0.44
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.88	D
M_CAP	Benign	0.014	T
MetaRNN	Benign	0.13	T
MetaSVM	Benign	-0.87	T
MutationAssessor	Benign	1.1	L
PhyloP100		7.9
PrimateAI	Uncertain	0.67	T
PROVEAN	Benign	-0.70	N
REVEL	Benign	0.16
Sift	Benign	0.22	T
Polyphen		0.91	P
Vest4		0.32
MVP		0.36
MPC		0.12
ClinPred		0.27	T
GERP RS		4.8
Mutation Taster		=89/11	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: rs377141765; hg19: chr2-179477175; COSMIC: COSV60240729; COSMIC: COSV60240729;