First-trimester ultrasound diagnosis of holoprosencephaly: three case reports

We present three cases of fetal holoprosencephaly diagnosed by transabdomin al and transvaginal ultrasound examinations at 10 and 13 weeks' gestation. The diagnosis was based on two sonographic criteria: first, the intracrania l finding of a single ventricle with a cerebral mantle and no visible midli ne structures but fusion of the thalami and corpus striatum; and, second, f acial abnormalities, including hypotelorism. The ultrasound findings were c onfirmed by embryoscopy before abortion in one case and by pathological exa mination after abortion in two cases. Chromosome study of the three fetuses showed trisomy 18, triploidy and mosaic 18p deletion and duplication.