rs878853955

Positions:

• chr19-55156310-T-C
• chr19-55156310-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM1 PM2 BP6

The NM_000363.5(TNNI3):​c.173A>G​(p.Lys58Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. K58N) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TNNI3 NM_000363.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:1
• Conservation: PhyloP100: 3.06

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 Uncertain_significance. Variant got 3 ACMG points.

• PM1: In a chain Troponin I, cardiac muscle (size 208) in uniprot entity TNNI3_HUMAN there are 86 pathogenic changes around while only 10 benign (90%) in NM_000363.5
• PM2: Very rare variant in population databases, with high coverage
• BP6: Variant 19-55156310-T-C is Benign according to our data. Variant chr19-55156310-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 237689.We mark this variant Likely_benign, oryginal submissions are: {Benign=1, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TNNI3	NM_000363.5	c.173A>G	p.Lys58Arg	missense_variant	5/8	ENST00000344887.10	NP_000354.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TNNI3	ENST00000344887.10	c.173A>G	p.Lys58Arg	missense_variant	5/8	1	NM_000363.5	ENSP00000341838	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 19, 2024

This sequence change replaces lysine, which is basic and polar, with arginine, which is basic and polar, at codon 58 of the TNNI3 protein (p.Lys58Arg). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TNNI3-related conditions. ClinVar contains an entry for this variant (Variation ID: 237689). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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. -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 28, 2023

The p.K58R variant (also known as c.173A>G), located in coding exon 5 of the TNNI3 gene, results from an A to G substitution at nucleotide position 173. The lysine at codon 58 is replaced by arginine, an amino acid with highly similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

not provided Benign:1

Benign, criteria provided, single submitter

clinical testing

GeneDx

Mar 03, 2015

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.091
CardioboostCm	Uncertain	0.66
BayesDel_addAF	Uncertain	0.14	D
BayesDel_noAF	Uncertain	-0.040
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.71	D;D
Eigen	Uncertain	0.35
Eigen_PC	Uncertain	0.35
FATHMM_MKL	Uncertain	0.83	D
LIST_S2	Benign	0.72	T;T
M_CAP	Pathogenic	0.32	D
MetaRNN	Uncertain	0.43	T;T
MetaSVM	Uncertain	0.49	D
MutationAssessor	Benign	1.8	L;.
MutationTaster	Benign	0.99	D;D
PrimateAI	Uncertain	0.78	T
PROVEAN	Benign	-0.78	N;.
REVEL	Uncertain	0.53
Sift	Benign	0.36	T;.
Sift4G	Benign	0.46	T;T
Polyphen		0.98	D;.
Vest4		0.18
MutPred		0.44		Loss of ubiquitination at K58 (P = 0.0047);.;
MVP		0.92
MPC		1.5
ClinPred		0.89	D
GERP RS		4.4
Varity_R		0.48

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs878853955; hg19: chr19-55667678;