A Case Report of in Utero Williams Syndrome Arterial Malformation

Williams syndrome (WS), an autosomal dominant condition linked to gene deletions on chromosome 7, can cause supravalvular aortic narrowing and death. WS-associated mutations are believed to disrupt arterial elastin fibers, causing smooth muscle malformation, endomysial fibrosis and severe hypertension. Previous studies demonstrated arterial ultrastructural anomalies in adult WS patients. It is not presently known if the arterial phenotype of WS is also present in utero.

A 34-week stillborn was delivered to a 28-year-old with genetically confirmed WS. Aortic tissue from the patient was compared with non-WS fetal aorta of similar gestational age using EM and light microscopy. Both sections were taken from the proximal aortic root. This demonstrated internal elastic lamina disruption, malformed elastic fibers, smooth muscle proliferation and abnormal collagen fibers, consistent with adult WS phenotype.

Our analysis indicated the cardiovascular changes of WS in a fetus as young as 34 weeks.