Pallister-Killian syndrome presenting through nuchal translucency screening for trisomy 21.

Pallister-Killian syndrome (tetrasomy 12p) is an uncommon aneuploidy, which may present in the prenatal period with an ultrasonographically detected fetal abnormality or following karyotyping for maternal age. We report a case that presented with increased nuchal translucency and hydrops at a first trimester screening scan for trisomy 21.