chr19-55154086-C-G

Position:

• chr19-55154086-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 6P and 1B. PM1 PM2 PM5 BP4

The NM_000363.5(TNNI3):​c.493G>C​(p.Glu165Gln) 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 benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E165K) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: TNNI3 NM_000363.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• 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]

TNNI3 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 5 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 chr19-55154086-C-T is described in Lovd as [Likely_pathogenic].
• BP4: Computational evidence support a benign effect (MetaRNN=0.39696017).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TNNI3	NM_000363.5	c.493G>C	p.Glu165Gln	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.493G>C	p.Glu165Gln	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: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 20, 2018

This variant is not present in population databases (ExAC no frequency). 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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with TNNI3-related disease. This sequence change replaces glutamic acid with glutamine at codon 165 of the TNNI3 protein (p.Glu165Gln). The glutamic acid residue is highly conserved and there is a small physicochemical difference between glutamic acid and glutamine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
CardioboostCm	Benign	0.070
BayesDel_addAF	Uncertain	0.10	D
BayesDel_noAF	Benign	-0.090
CADD	Benign	23
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.71	D;D
Eigen	Benign	0.15
Eigen_PC	Uncertain	0.28
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.95	D;D
M_CAP	Uncertain	0.12	D
MetaRNN	Benign	0.40	T;T
MetaSVM	Uncertain	0.080	D
MutationAssessor	Benign	1.3	L;.
PrimateAI	Uncertain	0.62	T
PROVEAN	Benign	-0.57	N;.
REVEL	Benign	0.29
Sift	Benign	0.32	T;.
Sift4G	Benign	0.45	T;T
Polyphen		0.56	P;.
Vest4		0.36
MutPred		0.32		Gain of loop (P = 0.0079);.;
MVP		0.90
MPC		0.89
ClinPred		0.88	D
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.56

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: rs1057521530; hg19: chr19-55665454;