chr2-178547654-T-C

Variant names:

• chr2-178547654-T-C
• rs727504528
• NM_001267550.2:c.93972A>G

Variant summary

Our verdict is Benign. The variant received -14 ACMG points: 0P and 14B. BP4_Strong BP6 BP7 BS1 BS2

The NM_001267550.2(TTN):​c.93972A>G​(p.Glu31324Glu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000359 in 1,613,878 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000038 (2 hom.)
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:5
• Conservation: PhyloP100: 0.394
• Publications: 0 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 -14 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.54).
• BP6: Variant 2-178547654-T-C is Benign according to our data. Variant chr2-178547654-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 178905.
• BP7: Synonymous conserved (PhyloP=0.394 with no splicing effect.
• BS1: Variant frequency is greater than expected in population mid. GnomAdExome4 allele frequency = 0.0000383 (56/1461614) while in subpopulation MID AF = 0.00624 (36/5768). AF 95% confidence interval is 0.00463. There are 2 homozygotes in GnomAdExome4. There are 24 alleles in the male GnomAdExome4 subpopulation. Median coverage is 34. This position passed quality control check.
• BS2: High Homozygotes in GnomAdExome4 at 2 AD,AR gene

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.93972A>G	p.Glu31324Glu	synonymous	Exon 339 of 363	NP_001254479.2	Q8WZ42-12
	TTN	NM_001256850.1		c.89049A>G	p.Glu29683Glu	synonymous	Exon 289 of 313	NP_001243779.1	Q8WZ42-1
	TTN	NM_133378.4		c.86268A>G	p.Glu28756Glu	synonymous	Exon 288 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.93972A>G	p.Glu31324Glu	synonymous	Exon 339 of 363	ENSP00000467141.1	Q8WZ42-12
	TTN	ENST00000446966.2	TSL:1	c.93816A>G	p.Glu31272Glu	synonymous	Exon 337 of 361	ENSP00000408004.2	A0A1B0GXE3
	TTN	ENST00000436599.2	TSL:1	c.93696A>G	p.Glu31232Glu	synonymous	Exon 337 of 361	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152146 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: 0.00

Gnomad OTH AF: 0.000957

GnomAD2 exomes AF: 0.0000121 AC: 3 AN: 248790 AF XY: 0.0000222

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000266

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000383 AC: 56 AN: 1461614 Hom.: 2 Cov.: 34 AF XY: 0.0000330 AC XY: 24 AN XY: 727098

African (AFR) AF: 0.0000299 AC: 1 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44718

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.0000580 AC: 5 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53402

Middle Eastern (MID) AF: 0.00624 AC: 36 AN: 5768

European-Non Finnish (NFE) AF: 0.00000809 AC: 9 AN: 1111798

Other (OTH) AF: 0.0000828 AC: 5 AN: 60370

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152264 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74438

African (AFR) AF: 0.00 AC: 0 AN: 41570

American (AMR) AF: 0.00 AC: 0 AN: 15278

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5172

South Asian (SAS) AF: 0.00 AC: 0 AN: 4824

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68012

Other (OTH) AF: 0.000947 AC: 2 AN: 2112

Alfa AF: 0.0000800 Hom.: 0

Bravo AF: 0.0000151

Asia WGS AF: 0.000289 AC: 1 AN: 3476

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	1	1	not provided (2)
-	-	2	not specified (2)
-	-	1	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G (1)
-	-	1	Cardiovascular phenotype (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.54
CADD	Benign	0.084
DANN	Benign	0.61
PhyloP100		0.39
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=84/16	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: rs727504528; hg19: chr2-179412381;