2-178633645-A-T

Variant names:

• chr2-178633645-A-T
• rs1438979717
• NM_001267550.2:c.42714T>A

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_Strong

The NM_001267550.2(TTN):​c.42714T>A​(p.His14238Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000161 in 1,612,828 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 Uncertain significance (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Synonymous variant affecting the same amino acid position (i.e. H14238H) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000017 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.785
• Publications: 1 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 -4 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.042334467).

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.42714T>A	p.His14238Gln	missense	Exon 232 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.37791T>A	p.His12597Gln	missense	Exon 182 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.35010T>A	p.His11670Gln	missense	Exon 181 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.42714T>A	p.His14238Gln	missense	Exon 232 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.42558T>A	p.His14186Gln	missense	Exon 230 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.42438T>A	p.His14146Gln	missense	Exon 230 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152138 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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.0000171 AC: 25 AN: 1460690 Hom.: 0 Cov.: 33 AF XY: 0.0000179 AC XY: 13 AN XY: 726610

African (AFR) AF: 0.00 AC: 0 AN: 33440

American (AMR) AF: 0.0000224 AC: 1 AN: 44648

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26110

East Asian (EAS) AF: 0.00 AC: 0 AN: 39444

South Asian (SAS) AF: 0.00 AC: 0 AN: 86222

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

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5760

European-Non Finnish (NFE) AF: 0.0000216 AC: 24 AN: 1111468

Other (OTH) AF: 0.00 AC: 0 AN: 60308

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152138 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74300

African (AFR) AF: 0.00 AC: 0 AN: 41454

American (AMR) AF: 0.00 AC: 0 AN: 15258

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5174

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

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: 0.0000147 AC: 1 AN: 68016

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	1	-	Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9 (1)
-	1	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.14	T
BayesDel_noAF	Benign	-0.43
CADD	Benign	12
DANN	Benign	0.86
Eigen	Benign	-0.70
Eigen_PC	Benign	-0.47
FATHMM_MKL	Benign	0.73	D
LIST_S2	Benign	0.80	T
M_CAP	Benign	0.0091	T
MetaRNN	Benign	0.042	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	-1.6	N
PhyloP100		0.79
PrimateAI	Uncertain	0.55	T
PROVEAN	Uncertain	-3.2	D
REVEL	Benign	0.12
Sift	Benign	0.73	T
Polyphen		0.0	B
Vest4		0.11
MutPred		0.39		Gain of disorder (P = 0.0839)
MVP		0.13
MPC		0.084
ClinPred		0.095	T
GERP RS		0.58
Mutation Taster		=56/44	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: rs1438979717; hg19: chr2-179498372;