AND LESLIE G. BIESECKER’

Persistent truncus arteriosus (TA) is an uncommon congenital cardiovascular malformation, which comprises between 0.4 % and 1 % of all congenital heart defects. Occurrence of TA in siblings has been reported infrequently. Twins concordant for isolated TA appear to have been reported only once previously. In this paper, we describe dizygotic twin females who were concordant for isolated TA. Received 29 May, revised 21 August,,accepted for publication 23 August 1990 Key wordr: heart defects. congenital; hydrops fetalis; prenatal diagnosis; truncus arteriosus, Persistent truncus arteriosus (TA) is an un-common congenital cardiovascular malfor-mation, which comprises between 0.4