Amniocentesis can be useful during the third trimester of pregnancy for antenatal diagnosis of Pallister-Killian syndrome: a case report.

Pallister-Killian syndrome (PKS) is an extremely rare genetic disease characterized cytogenetically by tetrasomy 12p mosaicism. We recently encountered a case of maternal hydramnios associated with congenital diaphragm hernia according to the prenatal diagnosis. Prenatal diagnosis revealed a non-mosaic 47, XY, i(12)(p10) karyotype at amniocentesis of G-band and M-FISH analysis. We performed chromosomal analysis in both interphase and metaphase cells from a cord blood lymphocyte specimen. Mosaic tetrasomy of chromosome 12p was supported by G-banding or FISH analysis. When fetal observations are performed in detail using 2D/3D US, PKS may be diagnosed. In addition, it is effective to perform amniocentesis during the third trimester of pregnancy.