chr2-178735960-T-G

Variant names:

• chr2-178735960-T-G
• rs375177753
• NM_001267550.2:c.14486A>C

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4 BP6

The NM_001267550.2(TTN):​c.14486A>C​(p.Gln4829Pro) variant causes a missense change. The variant allele was found at a frequency of 0.000191 in 1,613,746 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. Q4829K) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.00017 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00019 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:9 B:3
• Conservation: PhyloP100: 5.01
• 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: Likely_benign. The variant received -2 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.3407519).
• BP6: Variant 2-178735960-T-G is Benign according to our data. Variant chr2-178735960-T-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 197578.

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.14486A>C	p.Gln4829Pro	missense	Exon 50 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.13535A>C	p.Gln4512Pro	missense	Exon 48 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.10754A>C	p.Gln3585Pro	missense	Exon 47 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.14486A>C	p.Gln4829Pro	missense	Exon 50 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.14486A>C	p.Gln4829Pro	missense	Exon 50 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.14210A>C	p.Gln4737Pro	missense	Exon 48 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.000171 AC: 26 AN: 152190 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.000382

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.000112 AC: 28 AN: 248890 AF XY: 0.000104

Gnomad AFR exome AF: 0.0000646

Gnomad AMR exome AF: 0.0000580

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: 0.000193 AC: 282 AN: 1461556 Hom.: 0 Cov.: 35 AF XY: 0.000193 AC XY: 140 AN XY: 727058

African (AFR) AF: 0.0000597 AC: 2 AN: 33474

American (AMR) AF: 0.0000671 AC: 3 AN: 44716

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 39678

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

European-Finnish (FIN) AF: 0.0000187 AC: 1 AN: 53392

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.000240 AC: 267 AN: 1111780

Other (OTH) AF: 0.000149 AC: 9 AN: 60368

GnomAD4 genome AF: 0.000171 AC: 26 AN: 152190 Hom.: 0 Cov.: 32 AF XY: 0.000161 AC XY: 12 AN XY: 74352

African (AFR) AF: 0.00 AC: 0 AN: 41456

American (AMR) AF: 0.00 AC: 0 AN: 15270

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5184

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10626

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

European-Non Finnish (NFE) AF: 0.000382 AC: 26 AN: 68036

Other (OTH) AF: 0.00 AC: 0 AN: 2088

Alfa AF: 0.000294 Hom.: 0

Bravo AF: 0.000178

TwinsUK AF: 0.000539 AC: 2

ALSPAC AF: 0.000778 AC: 3

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000241 AC: 2

ExAC AF: 0.0000745 AC: 9

EpiCase AF: 0.000218

EpiControl AF: 0.000119

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	4	1	not provided (5)
-	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	-	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
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Benign	-0.20	T
BayesDel_noAF	Benign	-0.21
CADD	Uncertain	23
DANN	Benign	0.92
Eigen	Pathogenic	0.73
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Benign	0.68	T
M_CAP	Benign	0.038	D
MetaRNN	Benign	0.34	T
MetaSVM	Benign	-0.40	T
PhyloP100		5.0
PrimateAI	Uncertain	0.50	T
PROVEAN	Uncertain	-3.5	D
REVEL	Uncertain	0.40
Sift	Benign	0.25	T
Polyphen		0.91	P
Vest4		0.39
MVP		0.26
MPC		0.36
ClinPred		0.10	T
GERP RS		5.9
Mutation Taster		=12/88	disease causing

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: rs375177753; hg19: chr2-179600687;