NM_001267550.2:c.26408A>G

Variant names:

• chr2-178714366-T-C
• rs12693164
• NM_001267550.2:c.26408A>G

Variant summary

Our verdict is Benign. The variant received -20 ACMG points: 0P and 20B. BP4_Strong BP6_Very_Strong BA1

The NM_001267550.2(TTN):​c.26408A>G​(p.Asn8803Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.165 in 1,613,708 control chromosomes in the GnomAD database, including 24,588 homozygotes. In-silico tool predicts a benign outcome for this variant. 15/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Synonymous variant affecting the same amino acid position (i.e. N8803N) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.17 (2460 hom., cov: 32)
  • Exomes 𝑓: 0.16 (22128 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:22
• Conservation: PhyloP100: 0.816
• Publications: 23 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]

LOC124906100 (HGNC:):

ACMG classification

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

• BP4: Computational evidence support a benign effect (MetaRNN=0.003471017).
• BP6: Variant 2-178714366-T-C is Benign according to our data. Variant chr2-178714366-T-C is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 46777.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BA1: GnomAd4 highest subpopulation (EAS) allele frequency at 95% confidence interval = 0.419 is higher than 0.05.

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.26408A>G	p.Asn8803Ser	missense	Exon 91 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.25457A>G	p.Asn8486Ser	missense	Exon 89 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.22676A>G	p.Asn7559Ser	missense	Exon 88 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.26408A>G	p.Asn8803Ser	missense	Exon 91 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.26408A>G	p.Asn8803Ser	missense	Exon 91 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.26132A>G	p.Asn8711Ser	missense	Exon 89 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.168 AC: 25603 AN: 152090 Hom.: 2457 Cov.: 32

Gnomad AFR AF: 0.164

Gnomad AMI AF: 0.471

Gnomad AMR AF: 0.174

Gnomad ASJ AF: 0.131

Gnomad EAS AF: 0.434

Gnomad SAS AF: 0.234

Gnomad FIN AF: 0.0981

Gnomad MID AF: 0.123

Gnomad NFE AF: 0.154

Gnomad OTH AF: 0.169

GnomAD2 exomes AF: 0.180 AC: 44633 AN: 248314 AF XY: 0.181

Gnomad AFR exome AF: 0.163

Gnomad AMR exome AF: 0.176

Gnomad ASJ exome AF: 0.127

Gnomad EAS exome AF: 0.431

Gnomad FIN exome AF: 0.0959

Gnomad NFE exome AF: 0.150

Gnomad OTH exome AF: 0.167

GnomAD4 exome AF: 0.164 AC: 240109 AN: 1461500 Hom.: 22128 Cov.: 35 AF XY: 0.166 AC XY: 120553 AN XY: 727028

African (AFR) AF: 0.166 AC: 5545 AN: 33460

American (AMR) AF: 0.177 AC: 7914 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.128 AC: 3350 AN: 26128

East Asian (EAS) AF: 0.444 AC: 17631 AN: 39694

South Asian (SAS) AF: 0.229 AC: 19764 AN: 86250

European-Finnish (FIN) AF: 0.0935 AC: 4991 AN: 53388

Middle Eastern (MID) AF: 0.208 AC: 1198 AN: 5764

European-Non Finnish (NFE) AF: 0.152 AC: 169327 AN: 1111728

Other (OTH) AF: 0.172 AC: 10389 AN: 60370

GnomAD4 genome AF: 0.168 AC: 25616 AN: 152208 Hom.: 2460 Cov.: 32 AF XY: 0.170 AC XY: 12620 AN XY: 74414

African (AFR) AF: 0.163 AC: 6786 AN: 41532

American (AMR) AF: 0.174 AC: 2658 AN: 15284

Ashkenazi Jewish (ASJ) AF: 0.131 AC: 454 AN: 3472

East Asian (EAS) AF: 0.434 AC: 2243 AN: 5172

South Asian (SAS) AF: 0.233 AC: 1125 AN: 4824

European-Finnish (FIN) AF: 0.0981 AC: 1041 AN: 10612

Middle Eastern (MID) AF: 0.133 AC: 39 AN: 294

European-Non Finnish (NFE) AF: 0.154 AC: 10476 AN: 67998

Other (OTH) AF: 0.173 AC: 365 AN: 2110

Alfa AF: 0.163 Hom.: 9591

Bravo AF: 0.176

TwinsUK AF: 0.150 AC: 555

ALSPAC AF: 0.153 AC: 590

ESP6500AA AF: 0.158 AC: 595

ESP6500EA AF: 0.151 AC: 1240

ExAC AF: 0.179 AC: 21627

Asia WGS AF: 0.332 AC: 1157 AN: 3478

EpiCase AF: 0.153

EpiControl AF: 0.160

ClinVar

ClinVar submissions

Significance: Benign/Likely benign

Revision: criteria provided, multiple submitters, no conflicts

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

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.065
BayesDel_addAF	Benign	-0.66	T
BayesDel_noAF	Benign	-0.58
CADD	Benign	11
DANN	Benign	0.41
Eigen	Benign	-0.94
Eigen_PC	Benign	-0.80
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Benign	0.63	T
MetaRNN	Benign	0.0035	T
MetaSVM	Benign	-0.99	T
PhyloP100		0.82
PrimateAI	Benign	0.29	T
PROVEAN	Benign	-2.1	N
REVEL	Benign	0.19
Sift	Benign	0.057	T
Polyphen		0.018	B
Vest4		0.092
MPC		0.068
ClinPred		0.0055	T
GERP RS		2.3
Mutation Taster		=88/12	polymorphism (auto)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs12693164; hg19: chr2-179579093; COSMIC: COSV60101753; COSMIC: COSV60101753;