Abstract: Objective To explore the cytogenetic characteristics of Pallister-Killian syndrome (PKS). Methods Peripheral blood samples were collected for G-banding karyotype analysis. The source of abnormal fragments was identified by single nucleotide polymorphism-microarray (SNP array), and then confirmed by fluorescence in situ hybridization (FISH). Results An 8 -month-old girl visited the doctor for psychomotor retardation. She suffered from feeding difficulties, low muscle tension, abnormal facial appearance, low hairline, foot deformity, hearing loss and other clinical manifestations after birth. The G-banded karyotyping of peripheral blood chromosome showed mos 47, XX, +mar [ 18 ]/ 46, XX[ 82 ]. Affymetrix CytoScan 750K array analysis showed a mosaic duplication of the whole short arm of chromosome 12, indicating to be the 12p tetrasomy. FISH analysis confirmed that 48% of cells had four 12p signals. Conclusion? According to the clinical manifestations and routine peripheral blood karyotype analysis combined with SNP-array and FISH detection, PKS was diagnosed.

Key words: Pallister-Killian syndrome;? 12 p tetrasomy;? karyotype analysis;? single nucleotide polymorphismmicroarray;? fluorescence in situ hybridization