Prenatal sonographic diagnosis of isolated fetal ascites in cri‐du‐chat (5p‐) syndrome: A case report

: Isolated fetal ascites and cri-du-chat syndrome (CdCS; OMIM #123450) are two very rare conditions that, to our best knowledge, have never been reported together. Here, we describe a case of isolated fetal ascites detected in the first trimester ultrasound, with no other remarkable signs. After an extensive work-up (fetal ultrasound, serologies, Coombs test, and NIPT), an amniocentesis was performed and revealed an abnormal karyotype of 46,XX,del(5)(p15.2), characteristic of CdCS. We hypothesize that isolated fetal ascites has to be considered an antenatal ultrasonographic marker for CdCS, a finding that should be confirmed in further cases.