Conotruncal Heart Malformation

Defective development of the cardiac outflow tract results in congenital cardiac anomalies that are known clinically as conotruncal defects. Development of the outflow tract is complicated, and the large number of conotruncal malformations.

Conotruncal defects (CTDs) are a group of genetically and embryologically related heart malformations inherited as autosomal recessive trait which occur both in humans and dogs. This is a large group of malformations of the ventricular outflow region which includes subarterial ventricular septal defects, tetralogy of Fallot, and persistent truncus arteriosus. Similar CTDs have been reported in human families and in the keeshond breed of dog. The results of breeding experiments conducted in a colony of keeshond dogs with conotruncal septal defects confirmed the hereditary nature of the abnormality but were not consistent with any simple genetic hypothesis. Both the incidence and the severity of the conotruncal lesions increased with the severity of the parental defect.

Adapted from
1. The keeshond defect in cardiac conotruncal development is oligogenic. Petra Werner. Human Genetics. Volume 116, Number 5/April, 2005
2. A single major-gene defect underlying cardiac conotruncal malformations interferes with myocardial growth during embryonic development: studies in the CTD line of keeshond dogs. Patterson DF, Pexieder T, Schnarr WR, Navratil T, Alaili R.
3. Hereditary defects of the conotruncal septum in keeshond dogs: Pathologic and genetic studies. Donald F. Patterson DVM, DSc, FACC , Robert L. Pyle VMD, MSc , Lodewyk Van Mierop MD, FACC , Julius Melbin VMD, PhD and Marcia Olson BA