rs397517770

Variant names:

• chr2-178542338-C-T
• rs397517770
• NM_001267550.2:c.97418G>A

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BP4_Strong BP6 BS2

The NM_001267550.2(TTN):​c.97418G>A​(p.Arg32473His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000936 in 1,613,294 control chromosomes in the GnomAD database, including 4 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R32473C) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000046 (1 hom., cov: 32)
  • Exomes 𝑓: 0.000099 (3 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:4
• Conservation: PhyloP100: 7.91
• Publications: 4 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 -9 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.05919534).
• BP6: Variant 2-178542338-C-T is Benign according to our data. Variant chr2-178542338-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 47585.
• BS2: High Homozygotes in GnomAdExome4 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.97418G>A	p.Arg32473His	missense	Exon 349 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.92495G>A	p.Arg30832His	missense	Exon 299 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.89714G>A	p.Arg29905His	missense	Exon 298 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.97418G>A	p.Arg32473His	missense	Exon 349 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.97262G>A	p.Arg32421His	missense	Exon 347 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.97142G>A	p.Arg32381His	missense	Exon 347 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.0000460 AC: 7 AN: 152086 Hom.: 1 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00124

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.000174 AC: 43 AN: 247808 AF XY: 0.000245

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000291

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000562

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000892

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000986 AC: 144 AN: 1461090 Hom.: 3 Cov.: 32 AF XY: 0.000155 AC XY: 113 AN XY: 726794

African (AFR) AF: 0.0000299 AC: 1 AN: 33464

American (AMR) AF: 0.0000224 AC: 1 AN: 44672

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26122

East Asian (EAS) AF: 0.0000253 AC: 1 AN: 39576

South Asian (SAS) AF: 0.00147 AC: 127 AN: 86190

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53374

Middle Eastern (MID) AF: 0.000520 AC: 3 AN: 5764

European-Non Finnish (NFE) AF: 0.00000810 AC: 9 AN: 1111588

Other (OTH) AF: 0.0000331 AC: 2 AN: 60340

GnomAD4 genome AF: 0.0000460 AC: 7 AN: 152204 Hom.: 1 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74386

African (AFR) AF: 0.0000241 AC: 1 AN: 41556

American (AMR) AF: 0.00 AC: 0 AN: 15282

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5160

South Asian (SAS) AF: 0.00125 AC: 6 AN: 4816

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10604

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68000

Other (OTH) AF: 0.00 AC: 0 AN: 2108

Alfa AF: 0.0000282 Hom.: 0

Bravo AF: 0.0000264

ExAC AF: 0.000231 AC: 28

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	1	1	not provided (2)
-	-	2	not specified (2)
-	-	1	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.76
BayesDel_addAF	Benign	-0.22	T
BayesDel_noAF	Benign	-0.13
CADD	Uncertain	24
DANN	Uncertain	0.99
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	D
M_CAP	Benign	0.081	D
MetaRNN	Benign	0.059	T
MetaSVM	Uncertain	0.47	D
MutationAssessor	Pathogenic	4.1	H
PhyloP100		7.9
PrimateAI	Uncertain	0.67	T
PROVEAN	Uncertain	-3.8	D
REVEL	Uncertain	0.56
Sift	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.47
MutPred		0.79		Loss of MoRF binding (P = 0.0707)
MVP		0.49
MPC		0.52
ClinPred		0.42	T
GERP RS		6.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=98/2	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: rs397517770; hg19: chr2-179407065;