Kaur et al. (2014) performed a genome-wide expression analysis in skin fibroblasts of 17 PKS probands, using the Affymetrix Human Genome U133 plus 2.0 arrays. Robust multi-array average (RMA) method was used to normalize and summarize Affymetrix raw data. The normalized data were then analyzed by (PCA. The authors identified 354 differentially expressed genes in PKS probands and evidence for a critical region on 12p13.31. Furthermore, downregulation of ZFPM2, GATA6, and SOX9, and overexpression of IGFBP2 might be associated with PKS clinical phenotype (Kaur et al., 2014). This evidence concerns the gene SOX9 and tetrasomy 12p.