In total, 5 patients died in the neonatal period (one LCHAD deficiency, one N-acetyl-glutamate synthase (NAGS) deficiency, one type 1 citrullinemia, two non-ketotic hyperglycinemia) and 2 died later before 2 years of age (mitochondriopathies) (Table 9). Here, NAGS is linked to hyperammonemia due to N-acetylglutamate synthase deficiency.