rs150231219

Positions:

• chr2-178790021-C-T

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 1P and 5B. PP2 BP4_Strong BP6

The NM_001267550.2(TTN):​c.1895G>A​(p.Gly632Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000101 in 1,613,156 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 13/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000059 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00011 (1 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4 B:2
• Conservation: PhyloP100: -0.0400

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]

ACMG classification

Verdict is Likely_benign. Variant got -4 ACMG points.

• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), TTN. . Gene score misZ -1.1021 (greater than the threshold 3.09). Trascript score misZ 6.9794 (greater than threshold 3.09). GenCC has associacion of gene with dilated cardiomyopathy, tibial muscular dystrophy, early-onset myopathy with fatal cardiomyopathy, autosomal recessive centronuclear myopathy, hypertrophic cardiomyopathy, hypertrophic cardiomyopathy 9, TTN-related myopathy, dilated cardiomyopathy 1G, arrhythmogenic right ventricular cardiomyopathy, myopathy, myofibrillar, 9, with early respiratory failure, familial isolated dilated cardiomyopathy, childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndrome, autosomal recessive limb-girdle muscular dystrophy type 2J.
• BP4: Computational evidence support a benign effect (MetaRNN=0.042020887).
• BP6: Variant 2-178790021-C-T is Benign according to our data. Variant chr2-178790021-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 501631.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Benign=1, Uncertain_significance=4}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2	c.1895G>A	p.Gly632Asp	missense_variant	12/363	ENST00000589042.5	NP_001254479.2
TTN	NM_133379.5	c.1895G>A	p.Gly632Asp	missense_variant	12/46	ENST00000360870.10	NP_596870.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.1895G>A	p.Gly632Asp	missense_variant	12/363	5	NM_001267550.2	ENSP00000467141	P1
TTN	ENST00000360870.10	c.1895G>A	p.Gly632Asp	missense_variant	12/46	5	NM_133379.5	ENSP00000354117

Frequencies

GnomAD3 genomes AF: 0.0000657 AC: 10 AN: 152122 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000131

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000415

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000588

Gnomad OTH AF: 0.000957

GnomAD3 exomes AF: 0.000163 AC: 41 AN: 251186 Hom.: 0 AF XY: 0.000184 AC XY: 25 AN XY: 135768

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000145

Gnomad ASJ exome AF: 0.0000993

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.000653

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000123

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.000105 AC: 154 AN: 1460916 Hom.: 1 Cov.: 31 AF XY: 0.000125 AC XY: 91 AN XY: 726802

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.000179

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.000800

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000540

Gnomad4 OTH exome AF: 0.000149

GnomAD4 genome AF: 0.0000591 AC: 9 AN: 152240 Hom.: 0 Cov.: 32 AF XY: 0.0000537 AC XY: 4 AN XY: 74420

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.000131

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000415

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000588

Gnomad4 OTH AF: 0.000473

Alfa AF: 0.000148 Hom.: 0

Bravo AF: 0.0000529

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000233 AC: 2

ExAC AF: 0.000181 AC: 22

EpiCase AF: 0.000327

EpiControl AF: 0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:2 Benign:1

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Jun 16, 2020	This variant is associated with the following publications: (PMID: 30819905) -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Jan 27, 2022	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Apr 28, 2017	- -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 12, 2017

- -

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 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

Cardiomyopathy Benign:1

Benign, criteria provided, single submitter

clinical testing

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Apr 19, 2022

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.19
BayesDel_addAF	Benign	-0.40	T
BayesDel_noAF	Benign	-0.44
CADD	Benign	20
DANN	Benign	0.93
Eigen	Benign	-0.10
Eigen_PC	Benign	0.029
FATHMM_MKL	Benign	0.66	D
LIST_S2	Benign	0.49	T;T;T;.;T;T;T;T
M_CAP	Benign	0.026	D
MetaRNN	Benign	0.042	T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.98	T
MutationTaster	Benign	0.99	N;N;N;N;N;N;N
PrimateAI	Benign	0.42	T
PROVEAN	Benign	-2.2	N;N;.;.;N;N;.;D
REVEL	Benign	0.083
Sift	Uncertain	0.011	D;T;.;.;D;D;.;D
Sift4G	Uncertain	0.030	.;.;.;.;.;.;.;D
Polyphen		0.029, 0.51	.;.;.;B;.;.;B;P
Vest4		0.33
MVP		0.12
MPC		0.13
ClinPred		0.029	T
GERP RS		2.9

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

Publications

LitVar

Other links and lift over

dbSNP: rs150231219; hg19: chr2-179654748;