19-55151886-TT-GA

Variant names:

• chr19-55151886-TT-GA
• NM_000363.5:c.580_581delAAinsTC
• TNNI3 p.Asn194Ser

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PS1_Moderate PM1 PM5

The NM_000363.5(TNNI3):​c.580_581delAAinsTC​(p.Asn194Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely pathogenic in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. N194T) has been classified as Uncertain significance. The gene TNNI3 is included in the ClinGen Criteria Specification Registry.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TNNI3 NM_000363.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.24
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• hypertrophic cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• hypertrophic cardiomyopathy 7

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• dilated cardiomyopathy 2A

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• cardiomyopathy, familial restrictive, 1

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• dilated cardiomyopathy 1FF

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• dilated cardiomyopathy

  Inheritance: AR, AD Classification: STRONG Submitted by: ClinGen
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial isolated restrictive cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• arrhythmogenic right ventricular cardiomyopathy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Specifications for TNNI3 are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PS1: Transcript NM_000363.5 (TNNI3) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PM1: In a hotspot region, there are 14 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 30 uncertain in NM_000363.5
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr19-55151885-G-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 181602.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000363.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TNNI3	NM_000363.5	MANE Select	c.580_581delAAinsTC	p.Asn194Ser	missense	N/A	NP_000354.4

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TNNI3	ENST00000344887.10	TSL:1 MANE Select	c.580_581delAAinsTC	p.Asn194Ser	missense	N/A	ENSP00000341838.5	P19429
	TNNI3	ENST00000665070.1		c.613_614delAAinsTC	p.Asn205Ser	missense	N/A	ENSP00000499482.1	A0A590UJN1
	TNNI3	ENST00000714238.1		c.568_569delAAinsTC	p.Asn190Ser	missense	N/A	ENSP00000519518.1	A0AAQ5BHR0

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.2

Splicing

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr19-55663254;