TNNT1 and Friedreich ataxia: A downregulation of proteins specific of type 1 or slow-twitching fibers was observed in FRDA, including contractile proteins such as the myosin heavy chains MYH7 and MYH7B (Schiaffino, 2018), the troponin TNNT1 (Wei et al., 2014), and the calcium transporter ATP2A2 (Brandls et al., 1987).