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Gene

TNNI3

troponin I3, cardiac type

Summary

Cytogenetic location
19q13.42
Coordinates
Chromosome 19: 55,151,767–55,157,732 (GRCh38)
Exons
8 exons across 6 kb
Protein
210 amino acids
Inheritance
Autosomal dominant
Also known as
TNNC1, CMH7, cTNI
Previous symbols
CMD2A
MANE Select transcript
ENST00000344887.10NM_000363.5
Locus type
gene with protein product
  • Very high
  • Confident
  • Low
  • Very low

Reference genomeGRCh38

Positions on gene and variant pages follow this choice, in this browser.

Curated reports relevant to this gene

  • Dilated Cardiomyopathy

    • Enlargement and weakening of the left ventricle not explained by coronary artery or valve disease; inherited forms involve TTN, LMNA, RBM20, FLNC, BAG3, DSP, MYH7, TNNT2, DES, PLN and many other genes, and include Barth syndrome and the Emery-Dreifuss muscular dystrophies.

      • ClinGen rates the link strong
      • 3 GenCC submitters rate it definitive or strong
      What knowing changes

      Knowing a genetic cause supports earlier heart monitoring and family screening, and for genes with a high arrhythmia risk such as LMNA, FLNC and RBM20 it informs decisions about rhythm monitoring and implantable defibrillators.

  • Restrictive Cardiomyopathy

    • Familial Restrictive Cardiomyopathy 1 (TNNI3)Autosomal dominant

      A form of restrictive cardiomyopathy caused by changes in the sarcomere gene TNNI3.

      • 1 GenCC submitter rates it definitive or strong
      What knowing changes

      Knowing about it supports specialist heart monitoring and screening of relatives.

Broader groupings

  • Hypertrophic Cardiomyopathy

    • Autosomal dominant

      One of 62 genes linked to it

      A condition in which the myocardium is hypertrophied without an obvious cause. The hypertrophy is generally asymmetric and may be associated with obstruction of the ventricular outflow tract.

      • ClinGen rates the link definitive
      • 3 GenCC submitters rate it definitive or strong
      • On the ACMG secondary findings list
      What knowing changes

      Beta-blockers, non-dihydropyridine calcium channel blockers, activity restriction, genetic counseling

Inheritance

Autosomal dominant
One changed copy, from either parent, is enough. A parent who has one passes it on to each child with a one-in-two chance.

How TNNI3 is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Known disease-causing sites
  • Stretches short reads find hard
  • Variants with a page
Chromosome 19, with a bracket where TNNI3 sits. TNNI3 and 52 genes near it on chromosome 19, from 54,654,750 to 55,654,749.Chromosome 1919q13.42p13.3p13.2p13.13p13.12p13.11p12p11q11q12q13.11q13.12q13.13q13.2q13.31q13.32q13.33q13.41q13.42q13.4354.8 Mb55 Mb55.2 Mb55.4 Mb55.6 MbLILRB4: 54,643,889–54,670,531, forward strandLILRB4KIR3DL3: 54,724,442–54,736,632, forward strandKIR3DL3KIR2DL3: 54,738,505–54,753,061, forward strandKIR2DL3KIR2DL1: 54,769,793–54,784,332, forward strandKIR2DL1KIR2DL4: 54,803,610–54,814,517, forward strandKIR2DL4KIR3DL1: 54,816,440–54,830,778, forward strandKIR3DL1KIR2DS4: 54,832,676–54,848,569, forward strandKIR2DS4KIR3DL2: 54,850,433–54,867,209, forward strandKIR3DL2FCAR: 54,874,227–54,891,420, forward strandFCARNCR1: 54,906,112–54,941,199, forward strandNCR1NLRP7: 54,923,454–54,966,312, reverse strandNLRP7NLRP2: 54,953,130–55,001,142, forward strandNLRP2GP6: 55,012,055–55,038,264, reverse strandGP6RDH13: 55,039,108–55,071,291, reverse strandRDH13EPS8L1: 55,072,020–55,090,124, forward strandEPS8L1PPP1R12C: 55,090,913–55,117,679, reverse strandPPP1R12CTNNT1: 55,131,662–55,149,351, reverse strandTNNT1TNNI3: 55,151,767–55,157,732, reverse strandTNNI3: 55,154,757–55,160,671, reverse strandDNAAF3: 55,158,661–55,166,722, reverse strandDNAAF3SYT5: 55,171,196–55,180,328, reverse strandPTPRH: 55,181,230–55,209,512, reverse strandPTPRHTMEM86B: 55,226,524–55,228,784, reverse strandTMEM86BPPP6R1: 55,229,776–55,259,070, reverse strandPPP6R1HSPBP1: 55,262,219–55,280,930, reverse strandHSPBP1BRSK1: 55,282,072–55,312,592, forward strandBRSK1TMEM150B: 55,309,440–55,334,048, reverse strandTMEM150BKMT5C: 55,339,367–55,348,122, forward strandKMT5CCOX6B2: 55,349,306–55,354,754, reverse strandCOX6B2: 55,352,301–55,359,516, reverse strandGARIN5B: 55,354,908–55,363,260, reverse strandIL11: 55,364,382–55,370,463, reverse strandTMEM190: 55,376,816–55,378,246, forward strandTMEM238: 55,379,244–55,384,305, reverse strandRPL28: 55,383,856–55,403,342, forward strandUBE2S: 55,385,311–55,408,164, reverse strandUBE2SSHISA7: 55,428,740–55,452,900, reverse strandSHISA7ISOC2: 55,452,975–55,462,343, reverse strandISOC2C19orf85: 55,463,001–55,464,752, reverse strandC19orf85ZNF628: 55,476,597–55,484,487, forward strandZNF628NAT14: 55,484,949–55,487,578, forward strandSSC5D: 55,488,404–55,519,099, forward strandSBK2: 55,528,607–55,537,143, reverse strandSBK2SBK3: 55,539,018–55,550,284, reverse strandSBK3ZNF579: 55,576,774–55,580,921, reverse strandZNF579FIZ1: 55,591,371–55,606,194, reverse strandFIZ1ZNF524: 55,599,714–55,603,592, forward strandZNF524ZNF865: 55,605,502–55,617,269, forward strandZNF865ZNF784: 55,620,741–55,624,570, reverse strandZNF581: 55,624,664–55,647,294, forward strandZNF580: 55,635,003–55,643,470, forward strandCCDC106: 55,640,967–55,653,161, forward strandU2AF2: 55,654,115–55,674,717, forward strandDiagram of TNNI3: 8 exons on the reverse strand of chromosome 19Exon 8: 13 known disease-causing sitesExon 7: 25 known disease-causing sitesExon 6: 3 known disease-causing sitesExon 5: 7 known disease-causing sitesExon 4: 2 known disease-causing sitesExon 3: 4 known disease-causing sitesExon 1: 1 known disease-causing siteExon 8: 55,151,767–55,151,917, 151 bases. 6 variants with a page in exon 8. List themExon 7: 55,154,030–55,154,206, 177 bases. 10 variants with a page in exon 7. List themExon 6: 55,154,741–55,154,830, 90 basesExon 5: 55,156,201–55,156,332, 132 bases. 1 variant with a page in exon 5. List themExon 4: 55,156,603–55,156,644, 42 basesExon 3: 55,157,050–55,157,133, 84 basesExon 2: 55,157,296–55,157,308, 13 basesExon 1: 55,157,579–55,157,732, 154 bases. 1 variant with a page in exon 1. List them876543215′3′

Exons of the gene's MANE Select transcript (release v1.5), from NCBI and EMBL-EBI, on the GRCh38 reference genome.

Chromosome bands from UCSC's GRCh38 ideogram (2022-10-29).

Nearby genes from Ensembl release 116, on GRCh38.

Exons make up 0.8 kb of the gene's 6 kb; 633 of those bases code for the protein.

How a genome test reads TNNI3

66

positions in TNNI3 where ClinVar classes a change as pathogenic or likely pathogenic

None of them falls in a region short reads find hard.

A whole genome covers all 6 kb of TNNI3, introns included, not only the 0.8 kb of exons.

Variants with a page (18)

The TNNI3 variants with a page here, most review stars first. Each page describes ClinVar's public record of the variant, never a result.

VariantHGVS c.Exon or intronPosition (GRCh38)ClinVar classificationReview status
R162Qc.485G>AExon 755,154,094Likely pathogenic3 stars out of 4 reviewed by expert panel
R192Cc.574C>TExon 855,151,893Likely pathogenic3 stars out of 4 reviewed by expert panel
R192Hc.575G>AExon 855,151,892Pathogenic3 stars out of 4 reviewed by expert panel
A2Vc.5C>TExon 155,157,585Likely pathogenic2 stars out of 4 criteria provided, multiple submitters, no conflicts
A157Vc.470C>TExon 755,154,109Pathogenic2 stars out of 4 criteria provided, multiple submitters, no conflicts
D196Nc.586G>AExon 855,151,881Pathogenic/likely pathogenic2 stars out of 4 criteria provided, multiple submitters, no conflicts
L198Vc.592C>GExon 855,151,875Pathogenic/likely pathogenic2 stars out of 4 criteria provided, multiple submitters, no conflicts
R69Afs*8c.204delExon 555,156,278Pathogenic/likely pathogenic2 stars out of 4 criteria provided, multiple submitters, no conflicts
R141Qc.422G>AExon 755,154,157Pathogenic/likely pathogenic2 stars out of 4 criteria provided, multiple submitters, no conflicts
R145Gc.433C>GExon 755,154,146Pathogenic2 stars out of 4 criteria provided, multiple submitters, no conflicts

See all 18 TNNI3 variants →

Where this comes from

  • HGNC: the gene's symbol, name, other symbols and location.
  • MANE Select v1.5, from NCBI and EMBL-EBI: the transcript, its exons and coding sequence.
  • GenCC and ClinGen, released 2026-10-16: which conditions the gene is linked to, and how strongly.
  • The ACMG secondary findings list, SF v3.2.
  • ClinVar and the GIAB stratifications: known disease-causing sites, and the regions short reads find hard.
  • The Human Phenotype Ontology, release 2026-09-01: the traits linked to the gene. Find out more at hpo.jax.org.
  • Data release 2026.10.16-c6eea6bf.

Cite this page

APA

Dante Labs. (n.d.). TNNI3 gene: troponin I3, cardiac type. Retrieved 17 October 2026, from https://dantelabs.com/genes/tnni3

Vancouver

Dante Labs. TNNI3 gene: troponin I3, cardiac type [Internet]. [cited 17 October 2026]. Available from: https://dantelabs.com/genes/tnni3

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