Mosaic Intrachromosomal Triplication of (12)(p11.2p13) in a Patient with Pallister-Killian Syndrome

Pallister-Killian syndrome (PKS) is a rare genetic disorder usually characterized by mosaic tetrasomy of isochromosome 12p detected in cultured fibroblast cells. We describe here a patient with PKS and intrachromosomal triplication of the short arm of chromosome 12. Her karyo-type was mos 46, XX, inv trp(12)(p11.2p13)[34]/46, XX[16] de novo by conventional cytogenetics and fluorescent in situ hybridization (FISH) analysis. However, this chromosomal abnormality was not detected from the patient's cultured blood lymphocytes. We report here the third patient with intrachromosomal triplication on the short arm of chromosome 12, presenting a PKS phenotype.