Comparative study of mouse trisomy 16 and bis-Diamine treated fetuses: Discrimination of possible contribution of neural crest cells to malformations

In order to directly compare the malformation complex induced by genetic and environmental factors, mouse trisomy 16 (Ts 16) fetuses and bis-diamine
treated (BDT) mouse fetuses in which pregnant females were orally dosed with 3.0 mg and 1.0 mg/B.W. (g) bisdiamine eight hours apart on 9 days of pregnancy, were examined. Cystic hygroma with generalized edema appeared
in most Ts 16 and in less than 50% of BDT fetuses. Blunt snout or facial cleft with aplasia or hypoplasia of the olfactory bulb was observed in BDT fetuses. The Thymus was markedly to moderately hypoplastic in Ts 16, and absent or markedly hypoplastic in BDT fetuses. Parathyroid glands were inclined to be unsettled in relative Location to the thyroid in Ts 16 and absent in BDT fetuses. Aortic arch abnormalities were present in approximately half of the cases of Ts 16 and in the majority of cases of BDT fetuses. In the conotruncal region, double outlet right ventricle and persistent truncus arteriosus were dominantly observed in Ts 16 and BDT fetuses, respectively. Atrioventricular septal defect was observed in every Ts 16 and in about 30% of BDT fetuses. These results indicate that not only environmental factors but also genetic factors can experimentally induce DiGeorge-like anomaly in mice. Abnormal development relevant to neural crest cells seems to occur typically in BDT fetuses, and incompletely in Ts 16 fetuses.