Objective of the study: To determine the prenatal ultrasound criteria of holoprosencephaly and their correlation with embryogenesis.
Material and methods: We report 12 cases of holoprosencephaly that have been discovered between January 1990 and June 1996 (eleven alobar holoprosencephalies and one semilobar holoprosencephaly) at La Grave Hospital, Toulouse.
Results: In all cases, severe facial anomalies have been (cyclopia, cebocephaly or ethmocephaly). Prenatal ultrasound diagnosis was based on the association of brain anomalies (wide monoventricular cavity, thalami fusion, lacking of median structures) and facial dysmorphia (hypotelorism, orbital anomalies, median cleft lip ...). Finding microcephaly was a frequent sign of holoprosencephaly (64% of all cases). Chromosomal abnormalities have been found in 36% of the fetuses (Trisomy 13 is the most common). All patients underwent therapeutic abortions.
Conclusion: Transvaginal sonography diagnosis can be made around the 14th to 16th week amenorrhea. An early diagnosis allows an easier pregnancy termination, when such severe anomalies are found. In order to provide genetic counseling, a cytogenetic study of the fetus is necessary.