Denouement and Discussion
Fetal Turner's Syndrome
In the fetus the main features of Turner's syndrome are gross lymphedema with large cervical fluidfilled sacs. The cervical sacs may be extremely large and are most likely associated with the webbing of the neck found in patients with Turner's syndrome. There have been reports of elevated α-fetoprotein levels in the amniotic fluid of fetuses with Turner's syndrome. Some believe that this is due to obtaining fluid from the cervical sac rather than the amniotic fluid. Although the majority of patients both with Turner's syndrome survive, a substantial number of fetuses with Turner's syndrome do not come to term. The reason for this is not known.
The karyotype in the majority of patients with Turner's syndrome is 45,X. However, 20% to 30% have various types of mosaicism including X/XX, X/XY, and X/XX/XY or a structurally altered chromosome such as an isochromosome X,