19-55157093-C-T

Position:

• chr19-55157093-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The ENST00000344887.10(TNNI3):​c.65G>A​(p.Arg22His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. R22G) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TNNI3 ENST00000344887.10 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.343

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 4 ACMG points.

• PM1: In a chain Troponin I, cardiac muscle (size 208) in uniprot entity TNNI3_HUMAN there are 154 pathogenic changes around while only 19 benign (89%) in ENST00000344887.10
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TNNI3	NM_000363.5	c.65G>A	p.Arg22His	missense_variant	3/8	ENST00000344887.10	NP_000354.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TNNI3	ENST00000344887.10	c.65G>A	p.Arg22His	missense_variant	3/8	1	NM_000363.5	ENSP00000341838	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1450316 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 720086

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.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Nov 10, 2010

The Arg22His variant has not been reported in the literature. Arginine (Arg) at position 22 is not 100% conserved across different species (one mammalian speci es as well as distantly related species carry a different amino acid), reducing the likelihood that the change is pathogenic. Furthermore, the effect of the Arg 22His variant cannot be assessed because of the presence of another variant. -

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 06, 2023

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 22 of the TNNI3 protein (p.Arg22His). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with dilated cardiomyopathy (PMID: 27532257). ClinVar contains an entry for this variant (Variation ID: 43398). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.30
CardioboostCm	Benign	0.0078
BayesDel_addAF	Benign	0.0090	T
BayesDel_noAF	Benign	-0.22
CADD	Benign	21
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.58	D
Eigen	Benign	0.15
Eigen_PC	Benign	0.11
FATHMM_MKL	Benign	0.50	D
LIST_S2	Uncertain	0.87	D
M_CAP	Pathogenic	0.60	D
MetaRNN	Uncertain	0.45	T
MetaSVM	Uncertain	0.088	D
MutationAssessor	Benign	0.81	L
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.71	T
PROVEAN	Benign	-0.51	N
REVEL	Uncertain	0.34
Sift	Uncertain	0.016	D
Sift4G	Uncertain	0.057	T
Polyphen		1.0	D
Vest4		0.17
MutPred		0.15		Loss of methylation at R22 (P = 0.0361);
MVP		0.87
MPC		0.81
ClinPred		0.70	D
GERP RS		3.0
Varity_R		0.056

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs397516360; hg19: chr19-55668461;