chr2-178547901-C-T

Variant names:

• chr2-178547901-C-T
• rs369899675
• NM_001267550.2:c.93725G>A

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 0P and 3B. BP4_Moderate BP6

The NM_001267550.2(TTN):​c.93725G>A​(p.Arg31242His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000044 in 1,613,638 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R31242C) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000042 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:2
• Conservation: PhyloP100: 7.91
• Publications: 7 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 -3 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.097479075).
• BP6: Variant 2-178547901-C-T is Benign according to our data. Variant chr2-178547901-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 165726.

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.93725G>A	p.Arg31242His	missense	Exon 339 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.88802G>A	p.Arg29601His	missense	Exon 289 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.86021G>A	p.Arg28674His	missense	Exon 288 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.93725G>A	p.Arg31242His	missense	Exon 339 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.93569G>A	p.Arg31190His	missense	Exon 337 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.93449G>A	p.Arg31150His	missense	Exon 337 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.0000658 AC: 10 AN: 152066 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000483

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000656

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000578

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.000957

GnomAD2 exomes AF: 0.000101 AC: 25 AN: 248684 AF XY: 0.000104

Gnomad AFR exome AF: 0.0000646

Gnomad AMR exome AF: 0.0000290

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00117

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000178

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000417 AC: 61 AN: 1461572 Hom.: 0 Cov.: 34 AF XY: 0.0000413 AC XY: 30 AN XY: 727066

African (AFR) AF: 0.0000598 AC: 2 AN: 33472

American (AMR) AF: 0.0000224 AC: 1 AN: 44712

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.000580 AC: 23 AN: 39676

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53388

Middle Eastern (MID) AF: 0.000347 AC: 2 AN: 5764

European-Non Finnish (NFE) AF: 0.0000288 AC: 32 AN: 1111806

Other (OTH) AF: 0.0000166 AC: 1 AN: 60368

GnomAD4 genome AF: 0.0000658 AC: 10 AN: 152066 Hom.: 0 Cov.: 33 AF XY: 0.0000808 AC XY: 6 AN XY: 74260

African (AFR) AF: 0.0000483 AC: 2 AN: 41400

American (AMR) AF: 0.0000656 AC: 1 AN: 15246

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

East Asian (EAS) AF: 0.000578 AC: 3 AN: 5186

South Asian (SAS) AF: 0.00 AC: 0 AN: 4824

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

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 68014

Other (OTH) AF: 0.000957 AC: 2 AN: 2090

Alfa AF: 0.0000404 Hom.: 0

Bravo AF: 0.0000416

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000120 AC: 1

ExAC AF: 0.000107 AC: 13

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	2	1	not provided (3)
-	-	1	Cardiovascular phenotype (1)
-	1	-	not specified (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
BayesDel_addAF	Benign	-0.27	T
BayesDel_noAF	Benign	-0.22
CADD	Benign	22
DANN	Benign	0.97
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.97	D
M_CAP	Benign	0.020	T
MetaRNN	Benign	0.097	T
MetaSVM	Uncertain	-0.13	T
MutationAssessor	Benign	1.2	L
PhyloP100		7.9
PrimateAI	Uncertain	0.69	T
PROVEAN	Uncertain	-3.5	D
REVEL	Uncertain	0.43
Sift	Uncertain	0.028	D
Polyphen		1.0	D
Vest4		0.40
MVP		0.57
MPC		0.52
ClinPred		0.23	T
GERP RS		5.9
Mutation Taster		=85/15	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: rs369899675; hg19: chr2-179412628; COSMIC: COSV59895531; COSMIC: COSV59895531;