NM_001267550.2:c.104347C>T

Variant names:

• chr2-178532268-G-A
• rs539735520
• NM_001267550.2:c.104347C>T

Variant summary

Our verdict is Benign. The variant received -20 ACMG points: 0P and 20B. BP4_Strong BP6_Very_Strong BS1 BS2

The NM_001267550.2(TTN):​c.104347C>T​(p.Leu34783Phe) variant causes a missense change. The variant allele was found at a frequency of 0.000452 in 1,613,850 control chromosomes in the GnomAD database, including 13 homozygotes. 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 Likely benign (★★). Synonymous variant affecting the same amino acid position (i.e. L34783L) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.00014 (1 hom., cov: 32)
  • Exomes 𝑓: 0.00048 (12 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:15
• Conservation: PhyloP100: 5.22
• Publications: 0 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: Benign. The variant received -20 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.0074152946).
• BP6: Variant 2-178532268-G-A is Benign according to our data. Variant chr2-178532268-G-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 282653.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS1: Variant frequency is greater than expected in population sas. GnomAd4 allele frequency = 0.000144 (22/152280) while in subpopulation SAS AF = 0.00435 (21/4824). AF 95% confidence interval is 0.00292. There are 1 homozygotes in GnomAd4. There are 20 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.
• BS2: High Homozygotes in GnomAdExome4 at 12 AD,AR gene

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.104347C>T	p.Leu34783Phe	missense	Exon 358 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.99424C>T	p.Leu33142Phe	missense	Exon 308 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.96643C>T	p.Leu32215Phe	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.104347C>T	p.Leu34783Phe	missense	Exon 358 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.104191C>T	p.Leu34731Phe	missense	Exon 356 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.104071C>T	p.Leu34691Phe	missense	Exon 356 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.000145 AC: 22 AN: 152162 Hom.: 1 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00435

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00104 AC: 259 AN: 248298 AF XY: 0.00151

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: 0.00

Gnomad OTH exome AF: 0.000166

GnomAD4 exome AF: 0.000484 AC: 707 AN: 1461570 Hom.: 12 Cov.: 40 AF XY: 0.000751 AC XY: 546 AN XY: 727078

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44722

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 39690

South Asian (SAS) AF: 0.00796 AC: 687 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53290

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

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111860

Other (OTH) AF: 0.000315 AC: 19 AN: 60370

GnomAD4 genome AF: 0.000144 AC: 22 AN: 152280 Hom.: 1 Cov.: 32 AF XY: 0.000269 AC XY: 20 AN XY: 74462

African (AFR) AF: 0.0000241 AC: 1 AN: 41562

American (AMR) AF: 0.00 AC: 0 AN: 15300

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5180

South Asian (SAS) AF: 0.00435 AC: 21 AN: 4824

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10604

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68024

Other (OTH) AF: 0.00 AC: 0 AN: 2110

Alfa AF: 0.0000286 Hom.: 0

Bravo AF: 0.0000151

ExAC AF: 0.00110 AC: 133

Asia WGS AF: 0.00202 AC: 7 AN: 3478

ClinVar

ClinVar submissions

Significance: Benign/Likely benign

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	-	3	not provided (3)
-	-	3	not specified (3)
-	-	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	Cardiomyopathy (1)
-	-	1	Early-onset myopathy with fatal cardiomyopathy (1)
-	-	1	Hypertrophic cardiomyopathy (1)
-	-	1	Myopathy, myofibrillar, 9, with early respiratory failure (1)
-	-	1	Primary dilated cardiomyopathy (1)
-	-	1	Tibial muscular dystrophy (1)
-	-	1	TTN-related disorder (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.24
BayesDel_addAF	Benign	-0.40	T
BayesDel_noAF	Benign	-0.34
CADD	Benign	19
DANN	Benign	0.96
Eigen	Uncertain	0.31
Eigen_PC	Uncertain	0.38
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Uncertain	0.90	D
M_CAP	Benign	0.029	D
MetaRNN	Benign	0.0074	T
MetaSVM	Benign	-0.68	T
MutationAssessor	Benign	0.0	N
PhyloP100		5.2
PrimateAI	Benign	0.48	T
PROVEAN	Uncertain	-2.5	N
REVEL	Benign	0.15
Sift	Uncertain	0.0080	D
Polyphen		0.93	P
Vest4		0.34
MutPred		0.16		Gain of catalytic residue at L33142 (P = 0.0422)
MVP		0.71
MPC		0.23
ClinPred		0.088	T
GERP RS		5.6
Mutation Taster		=85/15	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: rs539735520; hg19: chr2-179396995;