rs754767262

Variant names:

• chr2-178548721-G-A
• rs754767262
• NM_001267550.2:c.92905C>T

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 0P and 1B. BP6

The NM_001267550.2(TTN):​c.92905C>T​(p.Arg30969Trp) variant causes a missense change. The variant allele was found at a frequency of 0.0000155 in 1,613,804 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R30969Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000016 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1 O:1
• Conservation: PhyloP100: 5.74
• 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]

ENSG00000270277 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -1 ACMG points.

• BP6: Variant 2-178548721-G-A is Benign according to our data. Variant chr2-178548721-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 535689.

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	NM_001267550.2	MANE Select	c.92905C>T	p.Arg30969Trp	missense	Exon 339 of 363	NP_001254479.2
	TTN	NM_001256850.1		c.87982C>T	p.Arg29328Trp	missense	Exon 289 of 313	NP_001243779.1
	TTN	NM_133378.4		c.85201C>T	p.Arg28401Trp	missense	Exon 288 of 312	NP_596869.4

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	ENST00000589042.5	TSL:5 MANE Select	c.92905C>T	p.Arg30969Trp	missense	Exon 339 of 363	ENSP00000467141.1
	TTN	ENST00000446966.2	TSL:1	c.92749C>T	p.Arg30917Trp	missense	Exon 337 of 361	ENSP00000408004.2
	TTN	ENST00000436599.2	TSL:1	c.92629C>T	p.Arg30877Trp	missense	Exon 337 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152154 Hom.: 0 Cov.: 33

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: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00316

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000121 AC: 3 AN: 248854 AF XY: 0.0000148

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: 0.0000177

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000164 AC: 24 AN: 1461532 Hom.: 0 Cov.: 35 AF XY: 0.0000179 AC XY: 13 AN XY: 727062

African (AFR) AF: 0.00 AC: 0 AN: 33468

American (AMR) AF: 0.000112 AC: 5 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26128

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39692

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53354

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

European-Non Finnish (NFE) AF: 0.0000153 AC: 17 AN: 1111784

Other (OTH) AF: 0.00 AC: 0 AN: 60364

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152272 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74468

African (AFR) AF: 0.00 AC: 0 AN: 41554

American (AMR) AF: 0.00 AC: 0 AN: 15304

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5178

South Asian (SAS) AF: 0.00 AC: 0 AN: 4824

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

Middle Eastern (MID) AF: 0.00340 AC: 1 AN: 294

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68014

Other (OTH) AF: 0.00 AC: 0 AN: 2114

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000113

ExAC AF: 0.00000827 AC: 1

ClinVar

ClinVar submissions as Germline

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

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

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.24
BayesDel_addAF	Benign	-0.063	T
BayesDel_noAF	Benign	-0.23
CADD	Benign	23
DANN	Benign	0.96
Eigen	Pathogenic	0.81
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.97	D
M_CAP	Benign	0.047	D
MetaRNN	Uncertain	0.45	T
MetaSVM	Uncertain	-0.24	T
MutationAssessor	Pathogenic	3.6	H
PhyloP100		5.7
PrimateAI	Benign	0.40	T
PROVEAN	Pathogenic	-4.6	D
REVEL	Uncertain	0.38
Sift	Uncertain	0.0030	D
Polyphen		1.0	D
Vest4		0.46
MutPred		0.65		Loss of disorder (P = 0.0142)
MVP		0.50
MPC		0.38
ClinPred		0.91	D
GERP RS		5.2
Mutation Taster		=83/17	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: rs754767262; hg19: chr2-179413448; COSMIC: COSV60321197; COSMIC: COSV60321197;