NM_001267550.2:c.81105C>A

Variant names:

• chr2-178565027-G-T
• rs72648212
• NM_001267550.2:c.81105C>A

Variant summary

Our verdict is Benign. The variant received -10 ACMG points: 0P and 10B. BP4_Strong BP6 BP7 BS2

The NM_001267550.2(TTN):​c.81105C>A​(p.Thr27035Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000659 in 1,613,356 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.00042 (1 hom., cov: 33)
  • Exomes 𝑓: 0.00068 (2 hom.)
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4 B:14
• Conservation: PhyloP100: 1.10
• Publications: 1 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 -10 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.53).
• BP6: Variant 2-178565027-G-T is Benign according to our data. Variant chr2-178565027-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 47395.
• BP7: Synonymous conserved (PhyloP=1.1 with no splicing effect.
• BS2: High Homozygotes in GnomAdExome4 at 2 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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	NM_001267550.2	MANE Select	c.81105C>A	p.Thr27035Thr	synonymous	Exon 326 of 363	NP_001254479.2
	TTN	NM_001256850.1		c.76182C>A	p.Thr25394Thr	synonymous	Exon 276 of 313	NP_001243779.1
	TTN	NM_133378.4		c.73401C>A	p.Thr24467Thr	synonymous	Exon 275 of 312	NP_596869.4

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	ENST00000589042.5	TSL:5 MANE Select	c.81105C>A	p.Thr27035Thr	synonymous	Exon 326 of 363	ENSP00000467141.1
	TTN	ENST00000446966.2	TSL:1	c.80949C>A	p.Thr26983Thr	synonymous	Exon 324 of 361	ENSP00000408004.2
	TTN	ENST00000436599.2	TSL:1	c.80829C>A	p.Thr26943Thr	synonymous	Exon 324 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes AF: 0.000421 AC: 64 AN: 152074 Hom.: 1 Cov.: 33

Gnomad AFR AF: 0.0000965

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000590

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000721

Gnomad OTH AF: 0.000958

GnomAD2 exomes AF: 0.000487 AC: 121 AN: 248312 AF XY: 0.000527

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000785

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000809

Gnomad OTH exome AF: 0.000498

GnomAD4 exome AF: 0.000684 AC: 999 AN: 1461164 Hom.: 2 Cov.: 37 AF XY: 0.000681 AC XY: 495 AN XY: 726834

African (AFR) AF: 0.0000598 AC: 2 AN: 33448

American (AMR) AF: 0.000985 AC: 44 AN: 44660

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26112

East Asian (EAS) AF: 0.00 AC: 0 AN: 39684

South Asian (SAS) AF: 0.00 AC: 0 AN: 86122

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53386

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5758

European-Non Finnish (NFE) AF: 0.000837 AC: 930 AN: 1111632

Other (OTH) AF: 0.000381 AC: 23 AN: 60362

GnomAD4 genome AF: 0.000421 AC: 64 AN: 152192 Hom.: 1 Cov.: 33 AF XY: 0.000403 AC XY: 30 AN XY: 74394

African (AFR) AF: 0.0000963 AC: 4 AN: 41558

American (AMR) AF: 0.000589 AC: 9 AN: 15270

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5148

South Asian (SAS) AF: 0.00 AC: 0 AN: 4822

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10612

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

European-Non Finnish (NFE) AF: 0.000721 AC: 49 AN: 67994

Other (OTH) AF: 0.000948 AC: 2 AN: 2110

Alfa AF: 0.000638 Hom.: 0

Bravo AF: 0.000442

EpiCase AF: 0.000819

EpiControl AF: 0.00113

ClinVar

ClinVar submissions as Germline

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	-	6	not specified (6)
-	1	3	not provided (4)
-	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	Cardiovascular phenotype (1)
-	1	-	Dilated cardiomyopathy 1G (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	-0.53
CADD	Benign	0.19
DANN	Benign	0.80
PhyloP100		1.1
Mutation Taster		=86/14	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: rs72648212; hg19: chr2-179429754; COSMIC: COSV108173308;