ALX3 and neural tube defect: Four genes downregulated in KO-NTD embryos -compared to WT and KO-N embryos- were found in the list of genes associated with NTD (Fig. 2a, b): ALX homeobox 3 (Alx3), myristoylated alanine-rich C kinase substrate (Marcks), neurogenin 2 (Neurog2), and paired box 3 (Pax3).