rs397517661

Variant names:

• chr2-178584357-A-G
• rs397517661
• NM_001267550.2:c.65194T>C

Variant summary

Our verdict is Benign. The variant received -7 ACMG points: 0P and 7B. BP4_Moderate BP6 BS2

The NM_001267550.2(TTN):​c.65194T>C​(p.Phe21732Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000106 in 1,612,936 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 0.000033 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00011 (2 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:1
• Conservation: PhyloP100: 9.27
• 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 -7 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.07824555).
• BP6: Variant 2-178584357-A-G is Benign according to our data. Variant chr2-178584357-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 47220.
• 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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	NM_001267550.2	MANE Select	c.65194T>C	p.Phe21732Leu	missense	Exon 311 of 363	NP_001254479.2
	TTN	NM_001256850.1		c.60271T>C	p.Phe20091Leu	missense	Exon 261 of 313	NP_001243779.1
	TTN	NM_133378.4		c.57490T>C	p.Phe19164Leu	missense	Exon 260 of 312	NP_596869.4

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	ENST00000589042.5	TSL:5 MANE Select	c.65194T>C	p.Phe21732Leu	missense	Exon 311 of 363	ENSP00000467141.1
	TTN	ENST00000446966.2	TSL:1	c.65038T>C	p.Phe21680Leu	missense	Exon 309 of 361	ENSP00000408004.2
	TTN	ENST00000436599.2	TSL:1	c.64918T>C	p.Phe21640Leu	missense	Exon 309 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes AF: 0.0000329 AC: 5 AN: 152056 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: 0.00104

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.000262 AC: 65 AN: 247736 AF XY: 0.000342

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: 0.0000358

Gnomad OTH exome AF: 0.000332

GnomAD4 exome AF: 0.000114 AC: 166 AN: 1460880 Hom.: 2 Cov.: 32 AF XY: 0.000161 AC XY: 117 AN XY: 726698

African (AFR) AF: 0.00 AC: 0 AN: 33432

American (AMR) AF: 0.00 AC: 0 AN: 44700

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26110

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39642

South Asian (SAS) AF: 0.00175 AC: 151 AN: 86176

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53370

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5758

European-Non Finnish (NFE) AF: 0.00000450 AC: 5 AN: 1111364

Other (OTH) AF: 0.000149 AC: 9 AN: 60328

GnomAD4 genome AF: 0.0000329 AC: 5 AN: 152056 Hom.: 0 Cov.: 32 AF XY: 0.0000404 AC XY: 3 AN XY: 74270

African (AFR) AF: 0.00 AC: 0 AN: 41456

American (AMR) AF: 0.00 AC: 0 AN: 15254

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5138

South Asian (SAS) AF: 0.00104 AC: 5 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10624

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 67966

Other (OTH) AF: 0.00 AC: 0 AN: 2090

Alfa AF: 0.0000936 Hom.: 0

Bravo AF: 0.0000151

ExAC AF: 0.000290 AC: 35

Asia WGS AF: 0.000866 AC: 3 AN: 3478

EpiCase AF: 0.00

EpiControl AF: 0.0000594

ClinVar

ClinVar submissions as Germline

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	1	-	Cardiovascular phenotype (1)
-	-	1	not provided (1)
-	1	-	not specified (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Benign	-0.28	T
BayesDel_noAF	Benign	-0.18
CADD	Benign	22
DANN	Benign	0.97
Eigen	Pathogenic	0.93
Eigen_PC	Pathogenic	0.91
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D
M_CAP	Benign	0.032	D
MetaRNN	Benign	0.078	T
MetaSVM	Uncertain	-0.040	T
MutationAssessor	Uncertain	2.6	M
PhyloP100		9.3
PrimateAI	Uncertain	0.78	T
PROVEAN	Pathogenic	-4.8	D
REVEL	Uncertain	0.53
Sift	Uncertain	0.014	D
Polyphen		1.0	D
Vest4		0.42
MutPred		0.62		Gain of disorder (P = 0.1298)
MVP		0.58
MPC		0.50
ClinPred		0.20	T
GERP RS		6.0
Mutation Taster		=71/29	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: rs397517661; hg19: chr2-179449084;