NM_000363.5:c.497C>A

Variant names:

• chr19-55154082-G-T
• NM_000363.5:c.497C>A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PM5

The NM_000363.5(TNNI3):​c.497C>A​(p.Ser166Tyr) 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S166F) has been classified as 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: 3.53

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 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 chr19-55154082-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TNNI3	NM_000363.5	c.497C>A	p.Ser166Tyr	missense_variant	Exon 7 of 8	ENST00000344887.10	NP_000354.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TNNI3	ENST00000344887.10	c.497C>A	p.Ser166Tyr	missense_variant	Exon 7 of 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

Cardiovascular phenotype Uncertain:1

Feb 09, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.S166Y variant (also known as c.497C>A), located in coding exon 7 of the TNNI3 gene, results from a C to A substitution at nucleotide position 497. The serine at codon 166 is replaced by tyrosine, an amino acid with dissimilar properties. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.34
CardioboostCm	Benign	0.023
BayesDel_addAF	Uncertain	0.14	D
BayesDel_noAF	Uncertain	-0.040
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.95	D;D
Eigen	Uncertain	0.27
Eigen_PC	Benign	0.21
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Benign	0.82	T;T
M_CAP	Pathogenic	0.32	D
MetaRNN	Uncertain	0.59	D;D
MetaSVM	Uncertain	0.71	D
MutationAssessor	Uncertain	2.7	M;.
PrimateAI	Uncertain	0.61	T
PROVEAN	Uncertain	-3.9	D;.
REVEL	Pathogenic	0.68
Sift	Uncertain	0.0020	D;.
Sift4G	Uncertain	0.030	D;D
Polyphen		0.76	P;.
Vest4		0.58
MutPred		0.61		Loss of disorder (P = 0.0107);.;
MVP		0.94
MPC		1.8
ClinPred		0.97	D
GERP RS		3.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.92

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr19-55665450;