This monograph reviews advances in understanding the genetic basis of heritable disorders of the heart and vasculature, including hypertrophic cardiomyopathy, Marfan syndrome, conotruncal malformations, atrioventricular septal defects, supravalvular aortic stenosis, and the field defects associated with DiGeorge and velocardiofacial syndromes. The prognostic value and the functional effects of beta myosin heavy chain gene mutations in familial hypertrophic cardiomyopathy are discussed. The relation between Marfan syndrome and fibrillin mutations and that between supravalvular aortic stenosis and William syndromes and elastin mutations are reviewed, as is the presence of microdeletions in 22q11 in DiGeorge syndrome, velocardiofacial syndrome, and nonsyndromic patients with conotruncal malformations. The relation between neural crest cells and field defects are considered in the context of the genetic basis of Patch, a mutation that results in abnormal neural crest cell migration and conotruncal malformations. The role of transforming growth factor beta isoforms in cardiac morphogenesis is considered in the light of apparently normal morphogenesis in transforming growth factor beta 1 null mice.