rs774524898

Variant names:

• chr2-178531103-G-A
• rs774524898
• NM_001267550.2:c.105512C>T

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_Strong BP6

The NM_001267550.2(TTN):​c.105512C>T​(p.Thr35171Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000102 in 1,613,870 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 15/20 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. T35171T) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000072 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00010 (1 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4 B:5
• Conservation: PhyloP100: 8.16
• Publications: 2 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 -5 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.04579246).
• BP6: Variant 2-178531103-G-A is Benign according to our data. Variant chr2-178531103-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 203099.

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.105512C>T	p.Thr35171Ile	missense	Exon 358 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.100589C>T	p.Thr33530Ile	missense	Exon 308 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.97808C>T	p.Thr32603Ile	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.105512C>T	p.Thr35171Ile	missense	Exon 358 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.105356C>T	p.Thr35119Ile	missense	Exon 356 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.105236C>T	p.Thr35079Ile	missense	Exon 356 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.0000723 AC: 11 AN: 152176 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: 0.00124

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000735

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.000165 AC: 41 AN: 249188 AF XY: 0.000252

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: 0.0000620

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000105 AC: 153 AN: 1461694 Hom.: 1 Cov.: 34 AF XY: 0.000151 AC XY: 110 AN XY: 727130

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: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00108 AC: 93 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53402

Middle Eastern (MID) AF: 0.000347 AC: 2 AN: 5768

European-Non Finnish (NFE) AF: 0.0000486 AC: 54 AN: 1111856

Other (OTH) AF: 0.0000663 AC: 4 AN: 60374

GnomAD4 genome AF: 0.0000723 AC: 11 AN: 152176 Hom.: 0 Cov.: 32 AF XY: 0.0000673 AC XY: 5 AN XY: 74326

African (AFR) AF: 0.00 AC: 0 AN: 41444

American (AMR) AF: 0.00 AC: 0 AN: 15284

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5188

South Asian (SAS) AF: 0.00124 AC: 6 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10618

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

European-Non Finnish (NFE) AF: 0.0000735 AC: 5 AN: 68028

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

Alfa AF: 0.0000823 Hom.: 0

Bravo AF: 0.0000567

ExAC AF: 0.000190 AC: 23

EpiCase AF: 0.0000545

EpiControl AF: 0.000237

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	1	1	not provided (2)
-	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	Cardiovascular phenotype (1)
-	1	-	Dilated cardiomyopathy 1G (1)
-	1	-	Early-onset myopathy with fatal cardiomyopathy (1)
-	-	1	Myopathy, myofibrillar, 9, with early respiratory failure (1)
-	-	1	Tibial muscular dystrophy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Benign	-0.35	T
BayesDel_noAF	Benign	-0.32
CADD	Benign	18
DANN	Benign	0.94
Eigen	Benign	0.022
Eigen_PC	Benign	0.12
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Benign	0.83	T
M_CAP	Benign	0.049	D
MetaRNN	Benign	0.046	T
MetaSVM	Benign	-0.48	T
MutationAssessor	Benign	0.91	L
PhyloP100		8.2
PrimateAI	Benign	0.35	T
PROVEAN	Uncertain	-3.5	D
REVEL	Benign	0.25
Sift	Uncertain	0.022	D
Polyphen		0.0040	B
Vest4		0.17
MVP		0.33
MPC		0.094
ClinPred		0.19	T
GERP RS		3.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.8
Mutation Taster		=90/10	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: rs774524898; hg19: chr2-179395830;