rs1555863491

Variant names:

• chr19-55154067-G-A
• rs1555863491
• NM_000363.5:c.512C>T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PM5 PP3_Moderate

The NM_000363.5(TNNI3):​c.512C>T​(p.Ala171Val) 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A171T) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TNNI3 NM_000363.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.88

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 8 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 chr19-55154068-C-T is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.909

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TNNI3	NM_000363.5	c.512C>T	p.Ala171Val	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.512C>T	p.Ala171Val	missense_variant	Exon 7 of 8	1	NM_000363.5	ENSP00000341838.5

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1460504 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 726578

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hypertrophic cardiomyopathy Uncertain:1

Apr 05, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Missense variants that are absent from the ExAC population database have been shown to be significantly overrepresented in individuals with hypertrophic cardiomyopathy (PMID: 27532257). This sequence change replaces alanine with valine at codon 171 of the TNNI3 protein (p.Ala171Val). The alanine residue is highly conserved and there is a small physicochemical difference between alanine and valine. In summary, this variant is a novel missense change that affects a residue important for protein function. However, the available evidence is currently insufficient to determine its role 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 disruptive, but these predictions have not been confirmed by published functional studies. A different missense substitution at this codon (p.Ala171Thr) has been determined to be pathogenic (PMID: 12531876, 15961398, 16288990, 18423659, 27532257). This suggests that the alanine residue is critical for TNNI3 protein function and that other missense substitutions at this position may also be pathogenic. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a TNNI3-related disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.28
CardioboostCm	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.27
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.96	D;D
Eigen	Pathogenic	0.75
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	D;D
M_CAP	Pathogenic	0.42	D
MetaRNN	Pathogenic	0.91	D;D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Pathogenic	3.1	M;.
PrimateAI	Uncertain	0.72	T
PROVEAN	Uncertain	-3.5	D;.
REVEL	Pathogenic	0.81
Sift	Uncertain	0.0010	D;.
Sift4G	Uncertain	0.0090	D;D
Polyphen		1.0	D;.
Vest4		0.75
MutPred		0.67		Loss of ubiquitination at K174 (P = 0.0699);.;
MVP		0.98
MPC		1.7
ClinPred		0.99	D
GERP RS		3.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.90

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: rs1555863491; hg19: chr19-55665435; COSMIC: COSV99402930; COSMIC: COSV99402930;