Genetics of sonographically detected intrauterine fetal cystic hygromas.

Turner syndrome has been the only genetic abnormality reported in which intrauterine cystic hygromas occur. We have recently seen three patients in whom cystic hygromas were detected in utero, and which turned out to be due to Turner, Down, and Noonan syndromes respectively. As the finding of a fetal cystic hygroma occurs in a spectrum of genetic disorders, anatomic and cytogenetic studies are indicated for definitive diagnosis.