Fig. 2

Most appropriate tissue of analysis to inquire for neurodevelopmental disorders. A. Correlation analysis based on genes with median TPM > 1.5 between the TI (different regions of brain cortex) and all easily accessible TAs. The highest correlation coefficient was obtained by skin (r = 0.99). B. Based on the “NDD Genes from SysID (Primary ID Genes)” set, the Venn diagrams show the number of expressed genes (median TPM > 1.5) in TI (central nervous system) and different easily accessible TAs. Skin shows the highest number of expressed genes (86.6%). When all easily accessible TAs are considered, 1317 of the 1452 genes annotated in the NDD list (PI = phenotype of interest) are captured and only 135 genes are not covered in any of the considered TAs. C. Venn diagrams showing the number of transcripts (median TPM > 1.5) in TI (central nervous system) and different TAs. Based on the NDD gene list, skin shows the highest number of overlapping transcripts with TI. D. Expression in different developmental stages of genes not expressed in adult brain (GTEx median TPM < 1.5). There is a significant enrichment of genes with a maximum expression level in the prenatal stage (Table 1). Based on Allen Brain Atlas data SIK1, CCBE1, FOXP2, HPD, and ALG11 are expressed in the adult brain. *** p-value < 0.0001 RPKM = Reads Per Kilobase of transcript, per Million mapped reads