rs200029470

Variant names:

• chr2-178575889-T-G
• rs200029470
• NM_001267550.2:c.70243A>C

Variant summary

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

The NM_001267550.2(TTN):​c.70243A>C​(p.Met23415Leu) variant causes a missense change. The variant allele was found at a frequency of 0.0000105 in 1,613,608 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M23415T) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000096 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 4.22
• 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 -2 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.124258965).

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.70243A>C	p.Met23415Leu	missense	Exon 326 of 363	NP_001254479.2
	TTN	NM_001256850.1		c.65320A>C	p.Met21774Leu	missense	Exon 276 of 313	NP_001243779.1
	TTN	NM_133378.4		c.62539A>C	p.Met20847Leu	missense	Exon 275 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.70243A>C	p.Met23415Leu	missense	Exon 326 of 363	ENSP00000467141.1
	TTN	ENST00000446966.2	TSL:1	c.70087A>C	p.Met23363Leu	missense	Exon 324 of 361	ENSP00000408004.2
	TTN	ENST00000436599.2	TSL:1	c.69967A>C	p.Met23323Leu	missense	Exon 324 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152094 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: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000804 AC: 2 AN: 248814 AF XY: 0.00000741

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: 0.0000178

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000958 AC: 14 AN: 1461396 Hom.: 0 Cov.: 36 AF XY: 0.0000110 AC XY: 8 AN XY: 726986

African (AFR) AF: 0.00 AC: 0 AN: 33460

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39680

South Asian (SAS) AF: 0.00 AC: 0 AN: 86248

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: 0.0000126 AC: 14 AN: 1111640

Other (OTH) AF: 0.00 AC: 0 AN: 60356

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152212 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74412

African (AFR) AF: 0.00 AC: 0 AN: 41572

American (AMR) AF: 0.00 AC: 0 AN: 15278

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5154

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

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10622

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

European-Non Finnish (NFE) AF: 0.0000441 AC: 3 AN: 67972

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

Alfa AF: 0.00000527 Hom.: 0

Bravo AF: 0.0000113

ExAC AF: 0.00000827 AC: 1

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	1	-	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy (1)
-	1	-	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G (1)
-	1	-	Cardiovascular phenotype (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Benign	-0.11	T
BayesDel_noAF	Benign	-0.38
CADD	Benign	19
DANN	Benign	0.93
Eigen	Benign	-0.34
Eigen_PC	Benign	-0.028
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Benign	0.77	T
M_CAP	Benign	0.013	T
MetaRNN	Benign	0.12	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	-2.1	N
PhyloP100		4.2
PrimateAI	Uncertain	0.69	T
PROVEAN	Benign	-1.2	N
REVEL	Benign	0.18
Sift	Benign	0.85	T
Polyphen		0.0020	B
Vest4		0.50
MutPred		0.55		Loss of methylation at K21771 (P = 0.085)
MVP		0.27
MPC		0.080
ClinPred		0.25	T
GERP RS		5.8
Mutation Taster		=95/5	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: rs200029470; hg19: chr2-179440616;