Submissions for variant NM_001267550.2(TTN):c.105754C>T (p.Arg35252Ter)

gnomAD frequency: 0.00001  dbSNP: rs886043924

Total submissions: 5

Submitter	RCV	SCV	Clinical significance	Condition	Last evaluated	Review status	Method	Comment
Eurofins Ntd Llc (ga)	RCV000432472	SCV000342639	likely pathogenic	not provided	2016-06-21	criteria provided, single submitter	clinical testing
GeneDx	RCV000432472	SCV000534063	pathogenic	not provided	2022-05-27	criteria provided, single submitter	clinical testing	Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Has not been previously published as pathogenic or benign to our knowledge; Located in the M-line region of TTN in which the majority of loss of function variants have been associated with autosomal recessive titinopathies (Carmignac et al., 2007); This variant is associated with the following publications: (PMID: 17444505)
Invitae	RCV002519305	SCV003495511	likely pathogenic	Dilated cardiomyopathy 1G; Autosomal recessive limb-girdle muscular dystrophy type 2J	2023-12-06	criteria provided, single submitter	clinical testing	This sequence change creates a premature translational stop signal (p.Arg35252*) in the TTN gene. While this is not anticipated to result in nonsense mediated decay, it is expected to create a truncated TTN protein. This variant is present in population databases (no rsID available, gnomAD 0.01%). This premature translational stop signal has been observed in individual(s) with clinical features of congenital myopathy (PMID: 35387801). ClinVar contains an entry for this variant (Variation ID: 288511). This variant is located in the M band of TTN (PMID: 25589632). Truncating variants in this region have been previously reported in individuals affected with autosomal recessive myopathy and muscular dystrophy (PMID: 18948003, 23975875, 24395473). Truncating variants in this region have also been identified in individuals affected with autosomal dominant dilated cardiomyopathy and/or cardio-related conditions (PMID: 27869827, 32964742). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic.
Revvity Omics, Revvity	RCV000432472	SCV003812808	likely pathogenic	not provided	2022-04-21	criteria provided, single submitter	clinical testing
Ambry Genetics	RCV003165761	SCV003860984	likely pathogenic	Cardiovascular phenotype	2022-11-03	criteria provided, single submitter	clinical testing	The p.R26187* variant (also known as c.78559C>T), located in coding exon 185 of the TTN gene, results from a C to T substitution at nucleotide position 78559. This changes the amino acid from an arginine to a stop codon within coding exon 185. This exon is located in the M-band region of the N2-B isoform of the titin protein and is constitutively expressed in TTN transcripts (percent spliced in or PSI 100%). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. While truncating variants in TTN are present in 1-3% of the general population, truncating variants in the M-band have been reported in association with autosomal recessive titinopathies, primarily presenting with skeletal myopathy phenotypes (Ceyhan-Birsoy O et al. Neurology. 2013 Oct 1;81(14):1205-14; De Cid R et al. Neurology. 2015;85(24):2126-35). In addition, regardless of their position, TTN truncating variants encoded in constitutive exons (PSI >90%) have been found to be significantly associated with dilated cardiomyopathy (DCM), though truncating variants in the A-band are the most common cause of DCM (Herman DS et al. N. Engl. J. Med., 2012 Feb;366:619-28; Roberts AM et al. Sci Transl Med, 2015 Jan;7:270ra6; Schafer S et al. Nat. Genet., 2017 01;49:46-53). Based on the majority of available evidence to date, this variant is likely to be pathogenic in association with autosomal recessive titinopathy; however, the clinical significance of this alteration with respect to cardiomyopathy remains unclear. (Carmignac V et al. Ann Neurol, 2007 Apr;61:340-51). (Nallamilli BRR et al. Ann Clin Transl Neurol, 2018 Dec;5:1574-1587).