chr2-178633031-A-G

Variant names:

• chr2-178633031-A-G
• rs397517572
• NM_001267550.2:c.43100T>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.43100T>C​(p.Ile14367Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000378 in 1,612,934 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000040 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:7
• Conservation: PhyloP100: 7.26
• 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=0.16307956).

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.43100T>C	p.Ile14367Thr	missense	Exon 234 of 363	NP_001254479.2
	TTN	NM_001256850.1		c.38177T>C	p.Ile12726Thr	missense	Exon 184 of 313	NP_001243779.1
	TTN	NM_133378.4		c.35396T>C	p.Ile11799Thr	missense	Exon 183 of 312	NP_596869.4

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	ENST00000589042.5	TSL:5 MANE Select	c.43100T>C	p.Ile14367Thr	missense	Exon 234 of 363	ENSP00000467141.1
	TTN	ENST00000446966.2	TSL:1	c.42944T>C	p.Ile14315Thr	missense	Exon 232 of 361	ENSP00000408004.2
	TTN	ENST00000436599.2	TSL:1	c.42824T>C	p.Ile14275Thr	missense	Exon 232 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes AF: 0.0000132 AC: 2 AN: 152054 Hom.: 0 Cov.: 32

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: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000242 AC: 6 AN: 247698 AF XY: 0.0000223

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000872

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000562

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000179

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000404 AC: 59 AN: 1460762 Hom.: 0 Cov.: 32 AF XY: 0.0000413 AC XY: 30 AN XY: 726630

African (AFR) AF: 0.00 AC: 0 AN: 33428

American (AMR) AF: 0.000134 AC: 6 AN: 44696

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26112

East Asian (EAS) AF: 0.0000253 AC: 1 AN: 39544

South Asian (SAS) AF: 0.0000232 AC: 2 AN: 86198

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53352

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5752

European-Non Finnish (NFE) AF: 0.0000432 AC: 48 AN: 1111360

Other (OTH) AF: 0.0000332 AC: 2 AN: 60320

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152172 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74380

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

American (AMR) AF: 0.0000655 AC: 1 AN: 15270

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3466

East Asian (EAS) AF: 0.00 AC: 0 AN: 5156

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: 0.0000147 AC: 1 AN: 67972

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

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000151

ExAC AF: 0.0000165 AC: 2

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 (1)
-	1	-	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G (1)
-	1	-	Dilated cardiomyopathy 1G (1)
-	1	-	Early-onset myopathy with fatal cardiomyopathy (1)
-	1	-	Myopathy, myofibrillar, 9, with early respiratory failure (1)
-	1	-	not specified (1)
-	1	-	Tibial muscular dystrophy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Benign	-0.23	T
BayesDel_noAF	Benign	-0.37
CADD	Benign	21
DANN	Benign	0.92
Eigen	Uncertain	0.41
Eigen_PC	Uncertain	0.53
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.91	D
M_CAP	Benign	0.016	T
MetaRNN	Benign	0.16	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.79	N
PhyloP100		7.3
PrimateAI	Uncertain	0.59	T
PROVEAN	Uncertain	-3.2	D
REVEL	Benign	0.22
Sift	Benign	0.17	T
Polyphen		0.92	P
Vest4		0.46
MutPred		0.41		Gain of disorder (P = 0.0226)
MVP		0.52
MPC		0.21
ClinPred		0.13	T
GERP RS		6.0
Mutation Taster		=64/36	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: rs397517572; hg19: chr2-179497758;