2-178531487-C-T

Variant names:

• chr2-178531487-C-T
• rs370137295
• NM_001267550.2:c.105128G>A

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 0P and 3B. BP4_Moderate BP6

The NM_001267550.2(TTN):​c.105128G>A​(p.Arg35043His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000239 in 1,613,846 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R35043C) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.00018 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00025 (0 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6 B:2
• Conservation: PhyloP100: 7.91
• 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: Likely_benign. The variant received -3 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.16143191).
• BP6: Variant 2-178531487-C-T is Benign according to our data. Variant chr2-178531487-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 191812.

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.105128G>A	p.Arg35043His	missense	Exon 358 of 363	NP_001254479.2
	TTN	NM_001256850.1		c.100205G>A	p.Arg33402His	missense	Exon 308 of 313	NP_001243779.1
	TTN	NM_133378.4		c.97424G>A	p.Arg32475His	missense	Exon 307 of 312	NP_596869.4

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTN	ENST00000589042.5	TSL:5 MANE Select	c.105128G>A	p.Arg35043His	missense	Exon 358 of 363	ENSP00000467141.1
	TTN	ENST00000446966.2	TSL:1	c.104972G>A	p.Arg34991His	missense	Exon 356 of 361	ENSP00000408004.2
	TTN	ENST00000436599.2	TSL:1	c.104852G>A	p.Arg34951His	missense	Exon 356 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes AF: 0.000177 AC: 27 AN: 152174 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000483

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: 0.000566

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000279

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.000177 AC: 44 AN: 248978 AF XY: 0.000170

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000579

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.000466

Gnomad NFE exome AF: 0.000266

Gnomad OTH exome AF: 0.000166

GnomAD4 exome AF: 0.000246 AC: 359 AN: 1461554 Hom.: 0 Cov.: 41 AF XY: 0.000235 AC XY: 171 AN XY: 727088

African (AFR) AF: 0.0000299 AC: 1 AN: 33478

American (AMR) AF: 0.0000671 AC: 3 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.0000232 AC: 2 AN: 86258

European-Finnish (FIN) AF: 0.000544 AC: 29 AN: 53266

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.000286 AC: 318 AN: 1111856

Other (OTH) AF: 0.0000994 AC: 6 AN: 60372

GnomAD4 genome AF: 0.000177 AC: 27 AN: 152292 Hom.: 0 Cov.: 32 AF XY: 0.000161 AC XY: 12 AN XY: 74470

African (AFR) AF: 0.0000481 AC: 2 AN: 41556

American (AMR) AF: 0.00 AC: 0 AN: 15292

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5180

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.000566 AC: 6 AN: 10606

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

European-Non Finnish (NFE) AF: 0.000279 AC: 19 AN: 68038

Other (OTH) AF: 0.00 AC: 0 AN: 2116

Alfa AF: 0.000386 Hom.: 1

Bravo AF: 0.000102

TwinsUK AF: 0.00 AC: 0

ALSPAC AF: 0.000778 AC: 3

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000120 AC: 1

ExAC AF: 0.000199 AC: 24

EpiCase AF: 0.000382

EpiControl AF: 0.000119

ClinVar

ClinVar submissions as Germline

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	3	-	not provided (3)
-	1	1	not specified (2)
-	1	-	Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G (1)
-	-	1	Cardiovascular phenotype (1)
-	1	-	Tip-toe gait (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.22
BayesDel_addAF	Benign	-0.26	T
BayesDel_noAF	Benign	-0.21
CADD	Benign	21
DANN	Benign	0.87
Eigen	Uncertain	0.60
Eigen_PC	Uncertain	0.59
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.91	D
M_CAP	Benign	0.039	D
MetaRNN	Benign	0.16	T
MetaSVM	Uncertain	-0.12	T
MutationAssessor	Benign	0.97	L
PhyloP100		7.9
PrimateAI	Uncertain	0.49	T
PROVEAN	Uncertain	-3.5	D
REVEL	Uncertain	0.51
Sift	Benign	0.038	D
Polyphen		1.0	D
Vest4		0.42
MVP		0.42
MPC		0.51
ClinPred		0.15	T
GERP RS		5.5
Mutation Taster		=86/14	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: rs370137295; hg19: chr2-179396214; COSMIC: COSV60136685; COSMIC: COSV60136685;