The restrictive phenotype is a rare variant of HCM presentation accounting for about 2.5% of affected families and is generally associated with a poor prognosis; mutations in the MYH7 and TNNI3 genes encoding cardiac myosin II and TnI, respectively, were found previously in probands with complex cardiomyopathies with mild hypertrophy and severe restriction [34]. This evidence concerns the gene TNNI3 and cardiomyopathy.