**5. Conclusion**

CHDs occur in nearly 1% of newborns and in over 5% of fetuses that do not survive to term in the Western world (Hoffman 1995; Hoffman and Kaplan 2002). Due to advances in medicine, there is a growing number of children and adults living with CHDs who require lifelong healthcare (Hoffman and Kaplan 2002). Therefore, understanding the molecular mechanisms of heart development and the underlying causes of CHDs has immediate translational significance. BMP signaling pathways are critical regulators of heart development in species as varied as fruit flies, chickens, mice, and humans. Mutations in the BMP pathway have been identified in humans with CHDs. This review discussed the critical roles of BMP signaling pathways in cardiac specification from the mesoderm, myocardial wall formation, valve development, chamber septation, and outflow tract morphogenesis. Because cardiac morphogenesis and BMP signaling pathways are evolutionarily conserved, information gleaned from a variety of model systems provides valuable insight into human heart development and CHDs. In the future this insight may help develop diagnostic tests and therapeutic options for people with CHDs.
