It is worth noting that tics are not habitually associated with IEMs, hence have not been include in this article, despite the fact that few cases of patients with tics have been reported in the following IEMs: Lesch-Nyhan disease (83), juvenile neuronal ceroid-lipofuscinosis (84), pantothenate kinase-associated neurodegeneration (85), Wilson disease (86), POLG disease (87), mannosidosis (88), COASY-associated neurodegeneration (89), and Maple Syrup Urine Disease (90). This evidence concerns the gene PANK1 and Wilson disease.