chr2-178681645-G-GT

Position:

• chr2-178681645-G-GT

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP6_Moderate BS2

The NM_001267550.2(TTN):​c.33172+15_33172+16insA variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000938 in 1,599,628 control chromosomes in the GnomAD database, including 2 homozygotes. Variant has been reported in ClinVar as Benign (★).

• Frequency:
  • Genomes: 𝑓 0.000072 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000096 (2 hom.)
• Consequence: TTN NM_001267550.2 intron
• Clinical Significance: Benign criteria provided, single submitter B:1
• Conservation: PhyloP100: -0.624

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

Verdict is Likely_benign. Variant got -6 ACMG points.

• BP6: Variant 2-178681645-G-GT is Benign according to our data. Variant chr2-178681645-G-GT is described in ClinVar as [Benign]. Clinvar id is 1577688.Status of the report is criteria_provided_single_submitter, 1 stars.
• BS2: High Homozygotes in GnomAdExome4 at 2 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2	c.33172+15_33172+16insA		intron_variant		ENST00000589042.5	NP_001254479.2
LOC124906100	XR_007087318.1	n.2186-32102dup		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.33172+15_33172+16insA		intron_variant		5	NM_001267550.2	ENSP00000467141	P1
TTN-AS1	ENST00000659121.1	n.503-52852dup		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes AF: 0.0000724 AC: 11 AN: 151858 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000242

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00208

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000283 AC: 67 AN: 236918 Hom.: 2 AF XY: 0.000319 AC XY: 41 AN XY: 128476

Gnomad AFR exome AF: 0.0000663

Gnomad AMR exome AF: 0.0000321

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00227

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000911

Gnomad OTH exome AF: 0.000345

GnomAD4 exome AF: 0.0000960 AC: 139 AN: 1447652 Hom.: 2 Cov.: 31 AF XY: 0.000124 AC XY: 89 AN XY: 719856

Gnomad4 AFR exome AF: 0.0000928

Gnomad4 AMR exome AF: 0.0000243

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00146

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.03e-7

Gnomad4 OTH exome AF: 0.000217

GnomAD4 genome AF: 0.0000724 AC: 11 AN: 151976 Hom.: 0 Cov.: 32 AF XY: 0.0000942 AC XY: 7 AN XY: 74290

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00208

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000189

Asia WGS AF: 0.00202 AC: 7 AN: 3478

ClinVar

Significance: Benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Benign:1

Benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 19, 2024

- -

Computational scores

Source: dbNSFP v4.3

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

Publications

LitVar

Other links and lift over

dbSNP: rs559323758; hg19: chr2-179546372;