FBXL4 and Menkes disease: Our results extend the list recommended by Honzik [13] for neonatal MD diagnostics by at least 15 genes (MD-related: RRM2B, CLPB, ACAD9, FBXL4, PC, AIFM1, SLC25A12, MTND5, NDUFS6 and non MD-related: CPS1, PGAP2 and more).