Peripartum cardiomyopathy shares clinical features with idiopathic dilated cardiomyopathy, a disorder associated with mutations in more than 40 genes. This study shows that mutations in some of these genes, notably TTN, also have a strong association with this condition. Peripartum cardiomyopathy is marked by the development of maternal systolic heart failure late in pregnancy or early in the postpartum period. 1 , 2 The incidence varies from 1 in 100 to 1 in 300 in geographic hot spots, including Nigeria and Haiti, to 1 in 1000 to 1 in 4000 in Europe and the United States. The strongest known risk factors are the presence of preeclampsia, twin gestation, and advanced maternal age. Among patients with peripartum cardiomyopathy, heart failure can resolve but often does not: rates of death of 5 to 10% are common, and 4% of cardiac transplantations in the . . .