TNNI3 and cardiomyopathy, familial restrictive, 1: There are a number of mutations in genes encoding sarcomeric and cytoskeletal proteins, including TNNI3, ACTC, β-MHC, TNNT2, TNNC1, DES, MYH, MYL3, and CRYAB, that have been reported to be etiologically linked to RCM [5].