LAUSR

ingle ventricle heart defects (SVHDs) are the most severe type of congenital heart disease. 1 Through complex surgical procedures, patients with SVHDs can survive but ultimately have only one functional ventricle as either the left (hypoplastic left heart syndrome [HLHS]) or right (hypoplastic right heart syndrome [HRHS]) ventricle is hypoplastic. Prenatal diagnosis of SVHDs relies on ultrasound screening and fetal echocardiography. This complex imaging technology requires experienced physicians and sonographers along with costly equipment, which inevitably elevates the burden of health care expenditures and deepens the risk of health care inequity for socioeconomi-cally disadvantaged groups. Cell-free DNA/RNA in maternal blood can serve as a noninvasive diagnostic test to detect and predict fetal and maternal health conditions; however, their ability to identify a fetus with an SVHD is unknown. 2,3 In this study, we leveraged deep sequencing and patient-specific induced pluripotent stem cells (iPSCs) to identify cell-free RNA that could potentially be developed as noninvasive maternal biomarkers for prenatal detection of SVHDs. We hypothesized cardiac proliferation is dysregulated in patients with SVHDs. We compared the proliferation of iPSC-derived cardiomyocytes (iPSC-CMs) from individuals with SVHDs and healthy individuals. Under an institutional review board–approved protocol, we recruited healthy individuals (n=5) and patients with SVHD