In this case series study, we screened gene mutations in TNNI3, TNNT2, and DES, which have been shown to be pathogenic for RCM, in four pediatric patients with suspected RCM and whose transthoracic echocardiography (TTE) presented a similar restricted ventricular filling pattern. The gene discussed is TNNT2; the disease is cardiomyopathy, familial restrictive, 1.