Screening of human chromosome 21 genes in the dorsolateral prefrontal cortex of individuals with Down syndrome.

The aim of the current study was to identify the genes on human chromosome 21 (HC21) that may serve important functions in the pathogenesis of Down syndrome (DS). The microarray data GSE5390 were obtained from the Gene Expression Omnibus database, which contained 7 DS and 8 healthy normal samples. The data were then normalized and the differentially expressed genes (DEGs) were identified using the LIMMA package and Bonferroni correction. Furthermore, the DEGs underwent clustering and gene ontology analysis. Additionally, the locations of the DEGs on HC21 were confirmed using human genome 19 in the University of California, Santa Cruz Interaction Browser. A total of 25 upregulated and 275 downregulated genes were screened between DS and healthy samples with a false discovery rate of <0.05 and |logFC|>1. The expression levels of these genes in the two samples were different. In addition, the up‑ and downregulated genes were markedly enriched in organic substance biological processes (P=4.48x10‑10) and cell‑cell signaling (P=0.000227). Furthermore, 17 overexpressed genes were identified on the 21q21‑22 area, including COL6A2, TTC3 and ABCG1. Together, these observations suggest that 17 upregulated genes on HC21 may be involved in the development of DS and provide the basis for understanding this disability.