rs72647845

Variant names:

• chr2-178795197-G-A
• rs72647845
• NM_001267550.2:c.970C>T

Variant summary

Our verdict is Benign. The variant received -20 ACMG points: 0P and 20B. BP4_Strong BP6_Very_Strong BS1 BS2

The NM_001267550.2(TTN):​c.970C>T​(p.Pro324Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000411 in 1,614,166 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 Likely benign (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P324L) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0024 (3 hom., cov: 32)
  • Exomes 𝑓: 0.00020 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:17
• Conservation: PhyloP100: 9.52
• Publications: 8 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 Gene-Disease associations (from GenCC):

• dilated cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• dilated cardiomyopathy 1G

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
• early-onset myopathy with fatal cardiomyopathy

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, G2P
• TTN-related myopathy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• myopathy, myofibrillar, 9, with early respiratory failure

  Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, ClinGen, Ambry Genetics
• tibial muscular dystrophy

  Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet
• autosomal recessive limb-girdle muscular dystrophy type 2J

  Inheritance: AR Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet
• hypertrophic cardiomyopathy 9

  Inheritance: AD Classification: MODERATE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• autosomal recessive centronuclear myopathy

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• arrhythmogenic right ventricular cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• congenital myopathy

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• hereditary skeletal muscle disorder

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• hypertrophic cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen

ACMG classification

Our verdict: Benign. The variant received -20 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.00536263).
• BP6: Variant 2-178795197-G-A is Benign according to our data. Variant chr2-178795197-G-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 47678.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS1: Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.00245 (373/152310) while in subpopulation AFR AF = 0.00852 (354/41554). AF 95% confidence interval is 0.00779. There are 3 homozygotes in GnomAd4. There are 172 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.
• BS2: High Homozygotes in GnomAd4 at 3 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.970C>T	p.Pro324Ser	missense	Exon 7 of 363	NP_001254479.2
	TTN	NM_001256850.1		c.970C>T	p.Pro324Ser	missense	Exon 7 of 313	NP_001243779.1
	TTN	NM_133378.4		c.970C>T	p.Pro324Ser	missense	Exon 7 of 312	NP_596869.4

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	ENST00000589042.5	TSL:5 MANE Select	c.970C>T	p.Pro324Ser	missense	Exon 7 of 363	ENSP00000467141.1
	TTN	ENST00000446966.2	TSL:1	c.970C>T	p.Pro324Ser	missense	Exon 7 of 361	ENSP00000408004.2
	TTN	ENST00000436599.2	TSL:1	c.970C>T	p.Pro324Ser	missense	Exon 7 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes AF: 0.00245 AC: 373 AN: 152192 Hom.: 3 Cov.: 32

Gnomad AFR AF: 0.00854

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00105

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: 0.0000147

Gnomad OTH AF: 0.000957

GnomAD2 exomes AF: 0.000598 AC: 150 AN: 251010 AF XY: 0.000464

Gnomad AFR exome AF: 0.00855

Gnomad AMR exome AF: 0.000318

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: 0.000199 AC: 291 AN: 1461856 Hom.: 0 Cov.: 32 AF XY: 0.000184 AC XY: 134 AN XY: 727236

African (AFR) AF: 0.00723 AC: 242 AN: 33480

American (AMR) AF: 0.000313 AC: 14 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.0000126 AC: 14 AN: 1111986

Other (OTH) AF: 0.000348 AC: 21 AN: 60394

GnomAD4 genome AF: 0.00245 AC: 373 AN: 152310 Hom.: 3 Cov.: 32 AF XY: 0.00231 AC XY: 172 AN XY: 74478

African (AFR) AF: 0.00852 AC: 354 AN: 41554

American (AMR) AF: 0.00105 AC: 16 AN: 15304

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5182

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

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

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68036

Other (OTH) AF: 0.000947 AC: 2 AN: 2112

Alfa AF: 0.000600 Hom.: 1

Bravo AF: 0.00283

ESP6500AA AF: 0.0102 AC: 45

ESP6500EA AF: 0.00 AC: 0

ExAC AF: 0.000708 AC: 86

ClinVar

ClinVar submissions as Germline

Significance: Benign/Likely benign

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	-	8	not specified (8)
-	-	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	Early-onset myopathy with fatal cardiomyopathy (1)
-	-	1	Long QT syndrome;C0878544:Cardiomyopathy (1)
-	-	1	Myopathy, myofibrillar, 9, with early respiratory failure (1)
-	-	1	not provided (1)
-	-	1	Tibial muscular dystrophy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.35
BayesDel_addAF	Benign	-0.17	T
BayesDel_noAF	Uncertain	-0.010
CADD	Benign	22
DANN	Benign	0.79
Eigen	Pathogenic	0.71
Eigen_PC	Uncertain	0.65
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.91	D
MetaRNN	Benign	0.0054	T
MetaSVM	Uncertain	0.39	D
PhyloP100		9.5
PrimateAI	Uncertain	0.55	T
PROVEAN	Pathogenic	-4.7	D
REVEL	Uncertain	0.39
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.027	D
Polyphen		1.0	D
Vest4		0.23
MVP		0.69
MPC		0.46
ClinPred		0.10	T
GERP RS		6.2
PromoterAI		-0.0012	Neutral
Mutation Taster		=87/13	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: rs72647845; hg19: chr2-179659924;