Prenatal diagnosis of Pallister-Killian syndrome in one twin

Key Clinical Message Pallister‐Killian syndrome (PKS) is often incidentally diagnosed prenatally due to ultrasound abnormalities or advanced maternal age. Severely shortened limbs could be the most outstanding abnormal observation in a fetus with PKS. PKS can be detected with the highest mosaic ratio by chromosomal microarray analysis (CMA) on uncultured amniocytes prenatally.