Prenatal phenotypic overlap of Costello syndrome and severe Noonan syndrome by tri-dimensional ultrasonography

BACKGROUND: Prenatal diagnosis of multiple congenital anomalies is difficult, and usually molecular biology cannot immediately confirm the suspected syndrome. Fetal dysmorphology is useful tool in the diagnosis process, with limitations. METHODS: We report the thorough prenatal investigation by 2D and 3D ultrasonography in a case of suspected Costello syndrome. RESULTS: Prenatal abnormalities were: increased nuchal translucency, polyhydramnios, bilateral pyelectasis and ventriculomegaly. Ultrasonographic morphological fetal face analysis found abnormal thickness of the skin in the prefrontal area, thick dysplastic ears, thick lips and deep-set creases in the hands and feet. As Costello and Noonan syndromes overlap, a PTPN11 analysis was done, with presence of a mutation (T854C). CONCLUSION: Prenatal overlap of feature of severe Noonan syndrome and Costello syndrome is confirmed, with dysmorphological similarities, due to edema of fetal skin in face and extremities.