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TNNI3

Synonyms
CMD1FF, CMD2A, CMH7, RCM1, TNNC1, cTnI
External resources
Summary
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.

Variant counts

The variants found in rare patients tested by 3billion are classified and counted according to ACMG guidelines. The variants with over 5% variant frequency in population genome databases ( gnomAD, dbSNP, etc) are excluded.

Pathogenic
56
Likely pathogenic
3
VUS
2,376
Likely benign
1,110
Benign
86

Patient phenotypes

Proportions of phenotypes among 55 patients carrying pathogenic or likely pathogenic variants on TNNI3 gene are displayed below.

Phenotype class
Patients in 3billion (%)
Abnormality of the cardiovascular system
72.7%
Abnormality of the nervous system
14.5%
Abnormality of the ear
10.9%
Abnormality of head or neck
5.5%
Abnormality of the musculoskeletal system
5.5%
Abnormality of the eye
3.6%
Abnormality of the genitourinary system
3.6%
Abnormal cellular phenotype
0%
Abnormality of blood and blood-forming tissues
0%
Abnormality of limbs
0%
Abnormality of metabolism homeostasis
0%
Abnormality of prenatal development or birth
0%
Abnormality of the breast
0%
Abnormality of the digestive system
0%
Abnormality of the endocrine system
0%
Abnormality of the immune system
0%
Abnormality of the integument
0%
Abnormality of the respiratory system
0%
Abnormality of the thoracic cavity
0%
Abnormality of the voice
0%
Constitutional symptom
0%
Growth abnormality
0%
Neoplasm
0%

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