NM_001267550.2:c.18075C>T

Variant names:

• chr2-178730325-G-A
• rs557350005
• NM_001267550.2:c.18075C>T

Variant summary

Our verdict is Benign. The variant received -21 ACMG points: 0P and 21B. BP4_Strong BP6_Very_Strong BP7 BS1 BS2

The NM_001267550.2(TTN):​c.18075C>T​(p.Pro6025Pro) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000241 in 1,610,940 control chromosomes in the GnomAD database, including 5 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Synonymous variant affecting the same amino acid position (i.e. P6025P) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.00016 (1 hom., cov: 33)
  • Exomes 𝑓: 0.00025 (4 hom.)
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:11
• Conservation: PhyloP100: 2.50
• Publications: 0 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: Benign. The variant received -21 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.74).
• BP6: Variant 2-178730325-G-A is Benign according to our data. Variant chr2-178730325-G-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 179179.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=2.5 with no splicing effect.
• BS1: Variant frequency is greater than expected in population sas. GnomAd4 allele frequency = 0.000164 (25/152222) while in subpopulation SAS AF = 0.00519 (25/4818). AF 95% confidence interval is 0.00361. There are 1 homozygotes in GnomAd4. There are 15 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.
• BS2: High Homozygotes in GnomAdExome4 at 4 AD,AR gene

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.18075C>T	p.Pro6025Pro	synonymous	Exon 62 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.17124C>T	p.Pro5708Pro	synonymous	Exon 60 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.14343C>T	p.Pro4781Pro	synonymous	Exon 59 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.18075C>T	p.Pro6025Pro	synonymous	Exon 62 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.18075C>T	p.Pro6025Pro	synonymous	Exon 62 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.17799C>T	p.Pro5933Pro	synonymous	Exon 60 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.000164 AC: 25 AN: 152104 Hom.: 1 Cov.: 33

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: 0.00518

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.000552 AC: 134 AN: 242950 AF XY: 0.000661

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000590

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000274

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000250 AC: 364 AN: 1458718 Hom.: 4 Cov.: 43 AF XY: 0.000358 AC XY: 260 AN XY: 725286

African (AFR) AF: 0.00 AC: 0 AN: 33438

American (AMR) AF: 0.0000451 AC: 2 AN: 44366

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26070

East Asian (EAS) AF: 0.00 AC: 0 AN: 39452

South Asian (SAS) AF: 0.00390 AC: 334 AN: 85734

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53278

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

European-Non Finnish (NFE) AF: 0.00000630 AC: 7 AN: 1110370

Other (OTH) AF: 0.000349 AC: 21 AN: 60258

GnomAD4 genome AF: 0.000164 AC: 25 AN: 152222 Hom.: 1 Cov.: 33 AF XY: 0.000202 AC XY: 15 AN XY: 74406

African (AFR) AF: 0.00 AC: 0 AN: 41550

American (AMR) AF: 0.00 AC: 0 AN: 15288

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5170

South Asian (SAS) AF: 0.00519 AC: 25 AN: 4818

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10606

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68002

Other (OTH) AF: 0.00 AC: 0 AN: 2114

Alfa AF: 0.000256 Hom.: 0

Bravo AF: 0.0000529

Asia WGS AF: 0.00231 AC: 8 AN: 3478

ClinVar

ClinVar submissions

Significance: Benign/Likely benign

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	-	3	not specified (3)
-	-	2	not provided (2)
-	-	1	Autosomal recessive limb-girdle muscular dystrophy type 2J (1)
-	-	1	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G (1)
-	-	1	Cardiomyopathy (1)
-	-	1	Early-onset myopathy with fatal cardiomyopathy (1)
-	-	1	Myopathy, myofibrillar, 9, with early respiratory failure (1)
-	-	1	Tibial muscular dystrophy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.74
CADD	Benign	5.1
DANN	Benign	0.63
PhyloP100		2.5
Mutation Taster		=96/4	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs557350005; hg19: chr2-179595052;