Cardiac developmental defects

Developmental defects have been produced in offspring of rats and hamsters treated in utero with urethane. Some of the malformations noted included eye, skeletal, neuronal tube defects, and cardiac malformations. 

CXCR4 has been deleted by at least three groups (25-27). In addition to confirming the phenotype of the SDF-1 knock-outs, the CXCR4-deleted mice have been observed to have a developmental defect in the migration of cells withing the cerebellum, retina, and certain ganglia in the cortex (Dan Littman, personal communication). Still unanswered is the proximal cause of embryonic and neonatal lethality in these animals, because the cardiac septal defect is compatible with life. 

Muscle, whose structure and function are discussed in Chapter 19, develops in response to four members of the myoD family. These include myoD, myogenin, myf5, and MRF4.417-419 All are muscle-specific transcription factors of the basic helix -loop -helix class. An unusual aspect of muscle development is formation of multinucleate myotubes (muscle fibers p. 1096)420 Apoptosis plays an important role in muscle development and can present significant complications in damaged cardiac muscle.421 Defects in several developmental control genes are responsible for congenital heart diseases.422... 

---