A 32-month-old girl with patent ductus arteriosus, false tendon of left ventricle, mild pulmonary hypertension, and chronic cardiac insufficiency (cardiac function level I-II) was misdiagnosed with Marfan Syndrome and there was no improvement in her physical growth after operation for this disease. The preterm baby was finally diagnosed with Myhre Syndrome by clinical phenotypes and mutation of SMAD4 gene.