ULTRASONOGRAPHIC PRENATAL-DIAGNOSIS OF THE 13Q-SYNDROME

A case is presented in which ultrasonographic examination led to the p renatal detection of a ring 13 chromosome in a fetus. At 18 weeks' ges tation, the fetus presented with holoprosencephaly, an abnormal config uration of the lower extremities, and an atrial septal defect. Althoug h the amount of amniotic fluid was normal, limb movements were never o bserved throughout pregnancy. The lower extremities were always flexed at the knee and talipes equinovarus was present. Hydrocephaly became apparent during the 2nd trimester. The ultrasonographic findings were confirmed by postpartum autopsy and X-ray examination. The ring chromo some was identified through amniocentesis and later verified in postpa rtum tissue.