19-55154071-G-C

Position:

• chr19-55154071-G-C

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP3_Strong PP5

The NM_000363.5(TNNI3):​c.508C>G​(p.Arg170Gly) variant causes a missense change involving the alteration of a non-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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R170Q) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: TNNI3 NM_000363.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:2
• Conservation: PhyloP100: 0.109

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]

TNNI3 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

• PM1: In a helix (size 25) in uniprot entity TNNI3_HUMAN there are 19 pathogenic changes around while only 0 benign (100%) in NM_000363.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr19-55154070-C-T is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.987
• PP5: Variant 19-55154071-G-C is Pathogenic according to our data. Variant chr19-55154071-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 165517.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=2, Likely_pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TNNI3	NM_000363.5	c.508C>G	p.Arg170Gly	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.508C>G	p.Arg170Gly	missense_variant	7/8	1	NM_000363.5	ENSP00000341838.5

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 31

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hypertrophic cardiomyopathy 7;C1861861:Cardiomyopathy, familial restrictive, 1;C2750091:Dilated cardiomyopathy 1FF Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

UCLA Clinical Genomics Center, UCLA

Feb 19, 2013

- -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

May 22, 2013

Variant classified as Uncertain Significance - Favor Pathogenic. The Arg170Gly v ariant in TNNI3 has not been reported in individuals with cardiomyopathy or in l arge population studies. Computational analyses (biochemical amino acid properti es, conservation, AlignGVGD, PolyPhen2, and SIFT) do not provide strong support for or against an impact to the protein. Of note, a different amino acid change at the same location, Arg170Gln, has been reported in one individual with HCM (K aski, 2009) and identified by our laboratory in 6 children with RCM (in 2 of the se, parental testing revealed de novo occurrence). This increases the likelihood that the Arg170Gly variant is disease causing; however, additional information is still needed to fully assess the clinical significance of this variant. -

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 13, 2021

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. This variant disrupts the p.Arg170 amino acid residue in TNNI3. Other variant(s) that disrupt this residue have been determined to be pathogenic (Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Experimental studies have shown that this variant affects TNNI3 protein function (PMID: 32182250). This variant has been observed in individual(s) with clinical features of TNNI3-related conditions (PMID: 25326637, 32182250). ClinVar contains an entry for this variant (Variation ID: 165517). This variant is not present in population databases (ExAC no frequency). This sequence change replaces arginine with glycine at codon 170 of the TNNI3 protein (p.Arg170Gly). The arginine residue is highly conserved and there is a moderate physicochemical difference between arginine and glycine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.90
CardioboostCm	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.46
CADD	Uncertain	23
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.97	D;D
Eigen	Benign	0.16
Eigen_PC	Benign	-0.059
FATHMM_MKL	Benign	0.22	N
LIST_S2	Pathogenic	1.0	D;D
M_CAP	Pathogenic	0.63	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.3	M;.
PrimateAI	Uncertain	0.70	T
PROVEAN	Pathogenic	-6.4	D;.
REVEL	Pathogenic	0.85
Sift	Pathogenic	0.0	D;.
Sift4G	Pathogenic	0.0010	D;D
Polyphen		0.99	D;.
Vest4		0.93
MutPred		0.90		Loss of MoRF binding (P = 0.0129);.;
MVP		0.94
MPC		1.9
ClinPred		1.0	D
GERP RS		-1.6
Varity_R		0.98

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: rs727503504; hg19: chr19-55665439;