Troponin T is the tropomyosin-binding subunit of troponin, the thin filament regulatory complex which confers calcium-sensitivity to striated muscle actomyosin ATPase activity. Additional isoforms seem to exist. In fetal and adult fast skeletal muscles, with a higher level expression in fetal than in adult muscle. The disease is caused by variants affecting the gene represented in this entry. Minor isoform detected in approximately 1% of cDNA clones. Belongs to the troponin T family.