Quantitation of biogenic amine metabolites in cerebrospinal fluid has enabled this investigator to evaluate and monitor treatment of various metabolic and degenerative disorders of the CNS. Patients studied include those with familial dystonic-Parkinsonism, infantile spasms, torsion dystonia, Hartnup disease, PKU variants and various dysautonomic conditions. Current studies include analysis of specific genetic mutations in children with aromatic amino acid decarboxylase deficiency and a detailed neuropsychiatric evaluation and molecular analysis of a large Texas family with GTP cyclohydrolast deficiency due to 37 bp deletion.