Biosynthesis and breakdown of serotonin and the catecholamines, and the metabolic block in<unk> , Wassenberg et al., 2017. Babies with severe<unk>  usually present during the first few months of life. Symptoms can include: * Hypotonia (floppiness) * Developmental delay * Oculogyric crises * Difficulty with initiating and controlling movements * Dystonia and dyskinesia * Gastointestinal dysmotility which can present at as vomiting, gastro-oesophageal reflux, diarrhoea and/or constipation * Autonomic symptoms including difficulties controlling temperature and blood sugar, excessive sweating and nasal congestion Some patients may develop cerebral folate deficiency, because O-methylation of the excessive amounts of L-Dopa can deplete methyl donors such as S-adenosyl methionine and levomefolic<unk> . This deviation can be detected by measuring the levels of levomefolic<unk>  in the cerebrospinal fluid, and can be corrected by folinic<unk> .
Aromatic L-amino acid decarboxylase deficiency
Arginine:glycine amidinotransferase deficiency
D-bifunctional protein deficiency
Beta-ketothiolase deficiency
Ornithine aminotransferase deficiency
Aldolase A deficiency
Short-chain acyl-coenzyme A dehydrogenase deficiency
Aminoacylase 1 deficiency