rs727503501

Positions:

• chr19-55154053-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The ENST00000344887.10(TNNI3):​c.526G>A​(p.Val176Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: TNNI3 ENST00000344887.10 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts P:1 U:2
• Conservation: PhyloP100: 7.82

Genes affected

TNNI3 (HGNC:11947): (troponin I3, cardiac type) Troponin I (TnI), along with troponin T (TnT) and troponin C (TnC), is one of 3 subunits that form the troponin complex of the thin filaments of striated muscle. TnI is the inhibitory subunit; blocking actin-myosin interactions and thereby mediating striated muscle relaxation. The TnI subfamily contains three genes: TnI-skeletal-fast-twitch, TnI-skeletal-slow-twitch, and TnI-cardiac. This gene encodes the TnI-cardiac protein and is exclusively expressed in cardiac muscle tissues. Mutations in this gene cause familial hypertrophic cardiomyopathy type 7 (CMH7) and familial restrictive cardiomyopathy (RCM). Troponin I is useful in making a diagnosis of heart failure, and of ischemic heart disease. An elevated level of troponin is also now used as indicator of acute myocardial injury in patients hospitalized with moderate/severe Coronavirus Disease 2019 (COVID-19). Such elevation has also been associated with higher risk of mortality in cardiovascular disease patients hospitalized due to COVID-19. [provided by RefSeq, Aug 2020]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a hotspot region, there are 11 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 14 uncertain in ENST00000344887.10
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.93

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TNNI3	NM_000363.5	c.526G>A	p.Val176Met	missense_variant	7/8	ENST00000344887.10	NP_000354.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TNNI3	ENST00000344887.10	c.526G>A	p.Val176Met	missense_variant	7/8	1	NM_000363.5	ENSP00000341838	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Primary familial hypertrophic cardiomyopathy Pathogenic:1

Likely pathogenic, no assertion criteria provided

clinical testing

Blueprint Genetics

May 05, 2014

- -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Jan 22, 2014

Variant classified as Uncertain Significance - Favor Pathogenic. The Val176Met v ariant in TNNI3 has been reported in 2 individuals with HCM (Lopes 2013) and has been now been identified by our laboratory in 2 individuals with HCM. It has no t been identified in large population studies. Computational analyses (biochemic al amino acid properties, conservation, AlignGVGD, and PolyPhen2) suggest that t his variant may impact the protein, though this information is not predictive en ough to determine pathogenicity. Although this data supports that the Val176Met variant may be pathogenic, additional studies are needed to fully assess its cli nical significance. -

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 23, 2019

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C15"). This variant has been observed in individual(s) with hypertrophic cardiomyopathy (PMID: 25524337, 27532257, 30384889, 23396983, Invitae). ClinVar contains an entry for this variant (Variation ID: 165513). This variant is not present in population databases (ExAC no frequency). This sequence change replaces valine with methionine at codon 176 of the TNNI3 protein (p.Val176Met). The valine residue is highly conserved and there is a small physicochemical difference between valine and methionine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.92
CardioboostCm	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Uncertain	0.11
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.97	D;D
Eigen	Pathogenic	0.86
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	1.0	D;D
M_CAP	Pathogenic	0.55	D
MetaRNN	Pathogenic	0.93	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.3	M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.87	D
PROVEAN	Uncertain	-2.9	D;.
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	D;.
Sift4G	Pathogenic	0.0	D;D
Polyphen		0.98	D;.
Vest4		0.90
MutPred		0.76		Loss of methylation at K177 (P = 0.0289);.;
MVP		0.98
MPC		1.7
ClinPred		0.99	D
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.2
Varity_R		0.95

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

Publications

LitVar

Other links and lift over

dbSNP: rs727503501; hg19: chr19-55665421;