Pallister-Killian syndrome (PKS) is a rare multiple congenital anomaly/intellectual deficit syndrome caused by mosaic tissue-limited tetrasomy for chromosome 12p. The disease is MONDO_0011146 (tetrasomy 12p). Also known as: Isochromosome 12p mosaicism, Isochromosome 12p syndrome, Pallister Killian Mosaic Syndrome, Pallister-Killian syndrome, Pallister-Killian syndrome, Somatic mosaicism, tetrasomy type 12p.