chr2-178615633-G-A

Variant names:

• chr2-178615633-G-A
• rs2288565
• NM_001267550.2:c.48460+8C>T

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.48460+8C>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00189 in 1,612,076 control chromosomes in the GnomAD database, including 96 homozygotes. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.0022 (6 hom., cov: 32)
  • Exomes 𝑓: 0.0019 (90 hom.)
• Consequence: TTN NM_001267550.2 splice_region, intron
• Scores: Splicing: ADA: 0.00006799
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:20
• Conservation: PhyloP100: -0.540
• Publications: 2 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 -20 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.86).
• BP6: Variant 2-178615633-G-A is Benign according to our data. Variant chr2-178615633-G-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 47022.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BA1: GnomAd4 highest subpopulation (EAS) allele frequency at 95% confidence interval = 0.051 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.48460+8C>T		splice_region intron	N/A	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.43537+8C>T		splice_region intron	N/A	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.40756+8C>T		splice_region intron	N/A	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.48460+8C>T		splice_region intron	N/A	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.48304+8C>T		splice_region intron	N/A	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.48184+8C>T		splice_region intron	N/A	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.00219 AC: 333 AN: 151868 Hom.: 6 Cov.: 32

Gnomad AFR AF: 0.000290

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000854

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.0564

Gnomad SAS AF: 0.00207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00334

GnomAD2 exomes AF: 0.00465 AC: 1152 AN: 247850 AF XY: 0.00409

Gnomad AFR exome AF: 0.000259

Gnomad AMR exome AF: 0.0000582

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0621

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000268

Gnomad OTH exome AF: 0.00200

GnomAD4 exome AF: 0.00186 AC: 2714 AN: 1460090 Hom.: 90 Cov.: 32 AF XY: 0.00179 AC XY: 1302 AN XY: 726308

African (AFR) AF: 0.0000300 AC: 1 AN: 33360

American (AMR) AF: 0.0000896 AC: 4 AN: 44650

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26072

East Asian (EAS) AF: 0.0621 AC: 2463 AN: 39644

South Asian (SAS) AF: 0.000814 AC: 70 AN: 86024

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53400

Middle Eastern (MID) AF: 0.000348 AC: 2 AN: 5750

European-Non Finnish (NFE) AF: 0.0000306 AC: 34 AN: 1110914

Other (OTH) AF: 0.00232 AC: 140 AN: 60276

GnomAD4 genome AF: 0.00217 AC: 330 AN: 151986 Hom.: 6 Cov.: 32 AF XY: 0.00249 AC XY: 185 AN XY: 74254

African (AFR) AF: 0.000289 AC: 12 AN: 41516

American (AMR) AF: 0.000852 AC: 13 AN: 15250

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

East Asian (EAS) AF: 0.0564 AC: 288 AN: 5108

South Asian (SAS) AF: 0.00207 AC: 10 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10584

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

European-Non Finnish (NFE) AF: 0.0000295 AC: 2 AN: 67910

Other (OTH) AF: 0.00236 AC: 5 AN: 2116

Alfa AF: 0.000871 Hom.: 3

Bravo AF: 0.00289

Asia WGS AF: 0.0170 AC: 58 AN: 3476

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	Tibial muscular dystrophy (2)
-	-	1	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G (1)
-	-	1	Cardiomyopathy (1)
-	-	1	Dilated cardiomyopathy 1G (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.86
CADD	Benign	3.8
DANN	Benign	0.59
PhyloP100		-0.54
Mutation Taster		=100/0	polymorphism (auto)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.000068
dbscSNV1_RF	Benign	0.0080
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: rs2288565; hg19: chr2-179480360; COSMIC: COSV104413385; COSMIC: COSV104413385;