rs397517756

Variant names:

• chr2-178548844-C-G
• rs397517756
• NM_001267550.2:c.92782G>C

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 0P and 1B. BP4

The NM_001267550.2(TTN):​c.92782G>C​(p.Asp30928His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000124 in 1,613,172 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). Synonymous variant affecting the same amino acid position (i.e. D30928D) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.00015 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00012 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:8 B:2
• Conservation: PhyloP100: 7.91
• 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]

ENSG00000270277 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -1 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.30935317).

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.92782G>C	p.Asp30928His	missense	Exon 339 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.87859G>C	p.Asp29287His	missense	Exon 289 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.85078G>C	p.Asp28360His	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.92782G>C	p.Asp30928His	missense	Exon 339 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.92626G>C	p.Asp30876His	missense	Exon 337 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.92506G>C	p.Asp30836His	missense	Exon 337 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.000151 AC: 23 AN: 152120 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

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: 0.000206

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.000105 AC: 26 AN: 248410 AF XY: 0.000104

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000290

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000222

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000121 AC: 177 AN: 1461052 Hom.: 0 Cov.: 34 AF XY: 0.000111 AC XY: 81 AN XY: 726842

African (AFR) AF: 0.00 AC: 0 AN: 33468

American (AMR) AF: 0.000224 AC: 10 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39670

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

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52886

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

European-Non Finnish (NFE) AF: 0.000139 AC: 155 AN: 1111790

Other (OTH) AF: 0.000199 AC: 12 AN: 60364

GnomAD4 genome AF: 0.000151 AC: 23 AN: 152120 Hom.: 0 Cov.: 33 AF XY: 0.000148 AC XY: 11 AN XY: 74312

African (AFR) AF: 0.00 AC: 0 AN: 41418

American (AMR) AF: 0.000590 AC: 9 AN: 15266

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5180

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

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

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

European-Non Finnish (NFE) AF: 0.000206 AC: 14 AN: 68016

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.000134 Hom.: 0

Bravo AF: 0.000283

TwinsUK AF: 0.000539 AC: 2

ALSPAC AF: 0.000259 AC: 1

ExAC AF: 0.000116 AC: 14

EpiCase AF: 0.000382

EpiControl AF: 0.000178

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	5	1	not provided (6)
-	1	-	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy (1)
-	1	-	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G (1)
-	-	1	Cardiovascular phenotype (1)
-	1	-	not specified (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.64
BayesDel_addAF	Benign	-0.12	T
BayesDel_noAF	Benign	-0.12
CADD	Benign	21
DANN	Benign	0.89
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.86
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D
M_CAP	Benign	0.033	D
MetaRNN	Benign	0.31	T
MetaSVM	Uncertain	0.21	D
MutationAssessor	Pathogenic	3.3	M
PhyloP100		7.9
PrimateAI	Uncertain	0.74	T
PROVEAN	Pathogenic	-5.2	D
REVEL	Uncertain	0.58
Sift	Uncertain	0.0090	D
Polyphen		1.0	D
Vest4		0.41
MVP		0.42
MPC		0.50
ClinPred		0.25	T
GERP RS		5.3
Mutation Taster		=53/47	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: rs397517756; hg19: chr2-179413571;