A GENETIC ASSESSMENT OF TRISOMY-21 IN A PATIENT WITH PERSISTENT TRUNCUS ARTERIOSUS WHO DIED 38 YEARS AGO

It is well known that in patients with Down syndrome there is a risk o f 40% to 50% of associated congenital heart disease.(1) The most frequ ent cardiac malformations are within the spectrum of either atrioventr icular septal defect (AVSD), otherwise known as atrioventricular canal , or ventricular septal defect (VSD).(2,3) Although the exact cause an d mechanism of these associations are not known, it has been hypothesi zed that, at least in some syndromes, there is a specific linkage of c ause and effect between chromosomal anomalies, altered genetic product , and congenital heart disease. The observation that some cardiac malf ormations are frequent and others unusual or absent in the same syndro mes, suggests that there may be a genetic influence on a specific phas e and segment of cardiac morphogenesis. Thus, anomaly or absence of a gene plays a role in the morphogenesis of certain components, but it d oes not change the development of other cardiovascular segments. For e xample, major conotruncal malformations, such as transposition of the great arteries or double-outlet right ventricle are extremely rare in trisomy 21.(3,4) In this report, we describe the case of a baby with t he extraordinary association of persistent truncus arteriosus, interru pted aortic arch, cleft of the mitral valve, and Down syndrome, in who m trisomy 21 was assessed by means of molecular biology 38 years after the patient's death.