Prospective ultrasound diagnosis of Pallister-Killian syndrome in the second trimester of pregnancy: the importance of the fetal facial profile

The Pallister-Killian syndrome (PKS) represents a rare polymalformative com plex characterized by a tissue-specific mosaic distribution of an additiona l isochromosome 12p and characterized by diaphragmatic hernia, rhizomelic l imb shortening, facial anomalies and, rarely, acral hypoplasia. Since diaph ragmatic hernia and acral hypoplasia can be also found in Fryns syndrome, t he differential diagnosis between the two conditions depends on the demonst ration of the 12p isochromosome by FISH. Prenatal diagnosis of PKS has been reported in cases submitted to karyotyping due to advanced maternal age or congenital anomalies detected on second trimester ultrasound. Among the ul trasound-detected malformations, little attention has been paid to facial a nomalies. We describe a case in which PKS was prospectively suspected on th e basis of the various anomalies detected at ultrasound, namely diaphragmat ic hernia, rhizomelic limb shortening, and abnormal facial profile. The dia gnosis was then confirmed by FISH on amniocytes and peripheral lymphocytes. In the present case, the disclosure of typical facial abnormalities signif icantly contributed to the differentiation between PKS and Fryns syndrome. Copyright (C) 2000 John Wiley & Sons, Ltd.