2-178745892-C-G

Position:

• chr2-178745892-C-G

Variant summary

Our verdict is Benign. Variant got -20 ACMG points: 0P and 20B. BP4_Strong BP6_Very_Strong BS1 BS2

The NM_133379.5(TTN):​c.16508G>C​(p.Ser5503Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00113 in 1,611,990 control chromosomes in the GnomAD database, including 18 homozygotes. In-silico tool predicts a benign outcome for this variant. 12/14 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★).

• Frequency:
  • Genomes: 𝑓 0.0059 (6 hom., cov: 32)
  • Exomes 𝑓: 0.00063 (12 hom.)
• Consequence: TTN NM_133379.5 missense
• Clinical Significance: Benign criteria provided, multiple submitters, no conflicts B:7
• Conservation: PhyloP100: 3.16

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:):

ACMG classification

Verdict is Benign. Variant got -20 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.005870104).
• BP6: Variant 2-178745892-C-G is Benign according to our data. Variant chr2-178745892-C-G is described in ClinVar as [Benign]. Clinvar id is 47803.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178745892-C-G is described in Lovd as [Benign]. Variant chr2-178745892-C-G is described in Lovd as [Likely_benign].
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00586 (891/152116) while in subpopulation AFR AF= 0.0205 (852/41548). AF 95% confidence interval is 0.0194. There are 6 homozygotes in gnomad4. There are 403 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.
• BS2: High Homozygotes in GnomAd4 at 6 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_133379.5	c.16508G>C	p.Ser5503Thr	missense_variant	46/46	ENST00000360870.10	NP_596870.2
TTN	NM_001267550.2	c.11312-3971G>C		intron_variant		ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000360870.10	c.16508G>C	p.Ser5503Thr	missense_variant	46/46	5	NM_133379.5	ENSP00000354117.4
TTN	ENST00000589042.5	c.11312-3971G>C		intron_variant		5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.00584 AC: 887 AN: 151998 Hom.: 6 Cov.: 32

Gnomad AFR AF: 0.0205

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000985

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: 0.000103

Gnomad OTH AF: 0.00766

GnomAD3 exomes AF: 0.00152 AC: 378 AN: 248990 Hom.: 4 AF XY: 0.00109 AC XY: 146 AN XY: 134466

Gnomad AFR exome AF: 0.0209

Gnomad AMR exome AF: 0.000814

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000712

Gnomad OTH exome AF: 0.000661

GnomAD4 exome AF: 0.000633 AC: 924 AN: 1459874 Hom.: 12 Cov.: 33 AF XY: 0.000555 AC XY: 403 AN XY: 726094

Gnomad4 AFR exome AF: 0.0230

Gnomad4 AMR exome AF: 0.000964

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000582

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000135

Gnomad4 OTH exome AF: 0.00143

GnomAD4 genome AF: 0.00586 AC: 891 AN: 152116 Hom.: 6 Cov.: 32 AF XY: 0.00542 AC XY: 403 AN XY: 74360

Gnomad4 AFR AF: 0.0205

Gnomad4 AMR AF: 0.000984

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000103

Gnomad4 OTH AF: 0.00758

Alfa AF: 0.00172 Hom.: 0

Bravo AF: 0.00674

ESP6500AA AF: 0.0182 AC: 80

ESP6500EA AF: 0.000233 AC: 2

ExAC AF: 0.00201 AC: 244

Asia WGS AF: 0.000577 AC: 2 AN: 3478

EpiCase AF: 0.0000546

EpiControl AF: 0.000119

ClinVar

Significance: Benign

Submissions summary: Benign:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:4

Benign, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Mar 16, 2012	Ser5503Thr in exon 45A of TTN: This variant is not expected to have clinical sig nificance because it has been identified in 1.9% (71/3738) of African American c hromosomes from a broad population by the NHLBI Exome Sequencing Project (http:/ /evs.gs.washington.edu/EVS; dbSNP rs16866489). -
Benign, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Dec 19, 2014	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -

not provided Benign:3

Benign, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Feb 04, 2021	- -
Benign, criteria provided, single submitter	not provided	Breakthrough Genomics, Breakthrough Genomics	-	- -
Likely benign, no assertion criteria provided	clinical testing	Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)	-	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.59	T
BayesDel_noAF	Benign	-0.60
CADD	Benign	22
DANN	Benign	0.96
Eigen	Benign	0.057
Eigen_PC	Benign	0.20
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Benign	0.35	T
MetaRNN	Benign	0.0059	T
MetaSVM	Benign	-1.1	T
PROVEAN	Benign	-0.10	N
REVEL	Benign	0.12
Sift	Benign	0.26	T
Sift4G	Benign	0.48	T
Polyphen		0.49	P
Vest4		0.25
MVP		0.44
ClinPred		0.018	T
GERP RS		5.1

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs16866489; hg19: chr2-179610619;