Dichorionic Diamniotic Twin Anencephaly and Exencephaly

Abstract

We present a rare case of dichorionic diamniotic twin anencephaly and exencephaly discovered in a 35-year-old female at 13.1 weeks of gestation. Anencephaly and exencephaly are neural tube defects (NTD) with devastating consequences caused by the failure of the anterior neural groove closure leading to exencephaly, followed by brain disintegration causing anencephaly. While NTD themselves are common congenital anomalies, their presence in both twins of a dichorionic diamniotic gestation is exceedingly rare and has only been documented in one other instance. The uncertainty surrounding risk factors involved in this specific case underscores the importance of ongoing research to elucidate other potential determinants in the pathogenesis of NTD and to discover novel preventive strategies, particularly in twin pregnancies. Future research endeavors should explore the interplay of genetic, environmental, and other anomalous factors to deepen our understanding and improve clinical outcomes for affected pregnancies.

Keywords: anencephaly; dichorionic diamniotic twins; dichorionic twin pregnancy; exencephaly; fetal anomalies; neural tube defects (ntds).

Figure 1. Ultrasound of twin A at 13.1 weeks gestation demonstrating anencephaly

Red arrow is pointing to the cranium.

Figure 2. 3D ultrasound of twin A at 13.1 weeks gestation demonstrating anencephaly

Figure 3. Ultrasound of twin B at 13.1 weeks gestation demonstrating exencephaly

Red arrow is pointing to the cranium.

Figure 4. 3D ultrasound of twin B at 13.1 weeks gestation demonstrating exencephaly