chr2-178566520-T-C

Variant names:

• chr2-178566520-T-C
• rs150682764
• NM_001267550.2:c.79612A>G

Variant summary

Our verdict is Benign. The variant received -16 ACMG points: 0P and 16B. BP4_Strong BP6_Very_Strong BS1

The NM_001267550.2(TTN):​c.79612A>G​(p.Thr26538Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000224 in 1,613,404 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts 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. T26538T) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.00099 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00014 (1 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:19
• Conservation: PhyloP100: 7.97
• Publications: 3 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 -16 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.008826554).
• BP6: Variant 2-178566520-T-C is Benign according to our data. Variant chr2-178566520-T-C is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 192152.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS1: Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.000992 (151/152158) while in subpopulation AFR AF = 0.00349 (145/41528). AF 95% confidence interval is 0.00303. There are 0 homozygotes in GnomAd4. There are 71 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.

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.79612A>G	p.Thr26538Ala	missense	Exon 326 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.74689A>G	p.Thr24897Ala	missense	Exon 276 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.71908A>G	p.Thr23970Ala	missense	Exon 275 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.79612A>G	p.Thr26538Ala	missense	Exon 326 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.79456A>G	p.Thr26486Ala	missense	Exon 324 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.79336A>G	p.Thr26446Ala	missense	Exon 324 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.000987 AC: 150 AN: 152040 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00348

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000197

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: 0.00

Gnomad OTH AF: 0.00143

GnomAD2 exomes AF: 0.000322 AC: 80 AN: 248318 AF XY: 0.000245

Gnomad AFR exome AF: 0.00472

Gnomad AMR exome AF: 0.000174

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000891

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000144 AC: 211 AN: 1461246 Hom.: 1 Cov.: 38 AF XY: 0.000131 AC XY: 95 AN XY: 726936

African (AFR) AF: 0.00559 AC: 187 AN: 33456

American (AMR) AF: 0.000201 AC: 9 AN: 44712

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26126

East Asian (EAS) AF: 0.00 AC: 0 AN: 39682

South Asian (SAS) AF: 0.00 AC: 0 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53206

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111698

Other (OTH) AF: 0.000199 AC: 12 AN: 60348

GnomAD4 genome AF: 0.000992 AC: 151 AN: 152158 Hom.: 0 Cov.: 33 AF XY: 0.000955 AC XY: 71 AN XY: 74374

African (AFR) AF: 0.00349 AC: 145 AN: 41528

American (AMR) AF: 0.000197 AC: 3 AN: 15250

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5164

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

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10614

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 67980

Other (OTH) AF: 0.00142 AC: 3 AN: 2114

Alfa AF: 0.000492 Hom.: 1

Bravo AF: 0.00122

ESP6500AA AF: 0.00474 AC: 18

ESP6500EA AF: 0.00 AC: 0

ExAC AF: 0.000414 AC: 50

Asia WGS AF: 0.000577 AC: 2 AN: 3478

ClinVar

ClinVar submissions

Significance: Benign/Likely benign

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	-	7	not specified (7)
-	-	3	not provided (3)
-	-	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	Cardiovascular phenotype (1)
-	-	1	Early-onset myopathy with fatal cardiomyopathy (1)
-	-	1	Myopathy, myofibrillar, 9, with early respiratory failure (1)
-	-	1	Primary dilated cardiomyopathy (1)
-	-	1	Tibial muscular dystrophy (1)
-	-	1	TTN-related disorder (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.38
BayesDel_addAF	Benign	-0.38	T
BayesDel_noAF	Benign	-0.32
CADD	Benign	20
DANN	Benign	0.88
Eigen	Uncertain	0.63
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.92	D
M_CAP	Benign	0.013	T
MetaRNN	Benign	0.0088	T
MetaSVM	Benign	-0.46	T
MutationAssessor	Benign	1.5	L
PhyloP100		8.0
PrimateAI	Benign	0.45	T
PROVEAN	Uncertain	-3.4	D
REVEL	Uncertain	0.38
Sift	Benign	0.10	T
Polyphen		1.0	D
Vest4		0.41
MVP		0.32
MPC		0.46
ClinPred		0.067	T
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Mutation Taster		=96/4	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: rs150682764; hg19: chr2-179431247;