Persistent truncus arteriosus in two siblings.

Congenital malformations, especially those of the heart, are among the important causes of death in the neonatal period and in childhood. The factors of heredity and environment have been discussed by numerous workers, and there are many reports about the incidence of congenital cardiac defects in one or both of twins and of more than one case of congenital cardiac disease occurring in the same family. Medvei and Rosler (1932) reviewed 37 cases of familial cardiac lesions and Courter et al. (1948) found 63 reports describing the occurrence of congenital heart disease in two members of a family. In 1958 Carleton et al. collected the reports of 141 affected families published since 1941 and added three cases of their own. Many authors have contributed cases including Ellis (1933), Lucksch and Stohr (1936), Kjaergaard (1946), Elshove (1951) and Bertoye et al. (1952). A number of workers have expressed their opinions on the importance of the environmental factor and on the problems of heredity. Maternal rubella during the first trimester of pregnancy appears to be the only proved environmental factor of much importance, for example Murphy (1947) collected 295 reports of congenital defects occurring after maternal rubella, including 117 malformations of the heart. The study of uniovular and biovular twins by Lamy et al. (1946) and Uchida and Rowe (1957), where in the majority of cases only one twin was affected, shows that heredity does not play a particularly important place in the production of congenital cardiac defects. Campbell (1959) reported 40 families with two or more cases of congenital heart disease and was impressed by the fact that the affected members of a family usually had the same type of malformation: he thought genetic factors the more important, probably not always decisive alone but becoming manifest under the influence of some environmental factor. An annotation in the British Medical Journal (1959) considers that, though suggestive, multiple familial occurrences does not prove that the defects have a genetic basis, as a whole family may be exposed to some particular environmental risk. The weight of evidence appears to favour both genetic and environmental factors as having some part in the etiology of congenital heart disease. Foxon (1959) concluded that it would be reasonable to suppose that there is more than one cause of congenital heart disease, and mentioned the interventricular septum that may be underdeveloped due to nutritional deficiency, or well developed but incorrectly aligned, and therefore incomplete, due to some genetic factor. The object of this paper is to present the case of a family in which the mother had a patent ductus arteriosus and two of her children had a persistent truncus arteriosus confirmed by necropsy. The only somewhat similar case has been reported by Giustra and Tosti (1939)-twin boys with true cor biloculare associated with a partial persistent truncus.