Multiple types of congenital heart defects-9 (CHTD9) is characterized by common arterial trunk (truncus arteriosus communis) in most patients, associated with other cardiac defects, including tetralogy of Fallot, interrupted aortic arch, right aortic arch, ventricular hypoplasia, and hypoplastic left heart, as well as other vascular and valvular anomalies (Ta-Shma et al., 2013; Guimier et al., 2023). For a general phenotypic description and discussion of genetic heterogeneity of multiple types of congenital heart defects, see CHTD1 (see 306955).