Metabolic diseases were observed in nine (6.2%) patients: three with citrullinemia, two with Leigh disease, one with ornithine transcarbamylase deficiency, one with pyridoxine dependent epilepsy, one with fumarase deficiency, and one with glutamate dehydrogenase 1 deficiency. This evidence concerns the gene GLUD1 and pyridoxine-dependent epilepsy.