Abstract: The copy number variation sequencing (CNV-Seq) technique can be used to explore the fetal marker chromosome and its possible source in the prenatal diagnosis. With this technique, we found a case of Pallister-Killian syndrome (PKS). We discuss the clinical and genetic characteristics of PKS. High-throughput sequencing of free DNA in the peripheral blood of pregnant woman, followed by amniocentesis, whole-genome copy number variation analysis of fetal DNA, and karyotype analysis of amniotic fluid cells to confirm PKS syndrome. A duplication of the most whole short arm of chromosome 12 was detected by CNV-seq in the fetal. The amniotic fluid karyotype was 47,XY,+i(12)(p10)[58]/46,XX[42]. CNV-seq as a first-line prenatal diagnostic technique can effectively find PKS, when combined with clinical features, karyotyping and other techniques.

Key words: Congenital abnormalities；Prenatal diagnosis；, Isochromosomes；, DNA copy number variations；, Pallister-Killian syndrome