NM_133379.5:c.11956C>A

Variant names:

• chr2-178750444-G-T
• rs200935937
• NM_133379.5:c.11956C>A

Variant summary

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

The NM_133379.5(TTN):​c.11956C>A​(p.Arg3986Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000548 in 1,460,564 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/17 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R3986C) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: TTN NM_133379.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.85
• Publications: 5 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=0.06710324).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_133379.5	c.11956C>A	p.Arg3986Ser	missense_variant	Exon 46 of 46	ENST00000360870.10	NP_596870.2
TTN	NM_001267550.2	c.11311+2680C>A		intron_variant	Intron 47 of 362	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000360870.10	c.11956C>A	p.Arg3986Ser	missense_variant	Exon 46 of 46	5	NM_133379.5	ENSP00000354117.4
TTN	ENST00000589042.5	c.11311+2680C>A		intron_variant	Intron 47 of 362	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.0000120 AC: 3 AN: 250000 AF XY: 0.0000148

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000581

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000548 AC: 8 AN: 1460564 Hom.: 0 Cov.: 73 AF XY: 0.00000826 AC XY: 6 AN XY: 726508

African (AFR) AF: 0.00 AC: 0 AN: 33404

American (AMR) AF: 0.0000448 AC: 2 AN: 44610

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26080

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39636

South Asian (SAS) AF: 0.0000464 AC: 4 AN: 86210

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53354

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111194

Other (OTH) AF: 0.0000166 AC: 1 AN: 60324

GnomAD4 genome Cov.: 32

ExAC AF: 0.0000165 AC: 2

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.34	T
BayesDel_noAF	Benign	-0.56
CADD	Benign	12
DANN	Benign	0.94
Eigen	Benign	-0.87
Eigen_PC	Benign	-0.80
FATHMM_MKL	Benign	0.26	N
LIST_S2	Benign	0.41	T
M_CAP	Benign	0.019	T
MetaRNN	Benign	0.067	T
MetaSVM	Benign	-1.0	T
PhyloP100		1.9
PROVEAN	Benign	0.82	N
REVEL	Benign	0.064
Sift	Benign	0.81	T
Sift4G	Benign	0.82	T
Polyphen		0.071	B
Vest4		0.24
MutPred		0.38		Loss of catalytic residue at R3986 (P = 0.1509);
MVP		0.49
ClinPred		0.048	T
GERP RS		2.5
Mutation Taster		=93/7	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: rs200935937; hg19: chr2-179615171;