RESUMEN
We report on a GTP cyclohydrolase 1 mutation-confirmed heterozygous case presenting with an infantile hypokinetic rigid syndrome and delay in attainment of motor milestones starting from the first year of life. He had a family history of dopa-responsive dystonia-parkinsonism. CSF neopterin, biopterin and HVA values were decreased. Molecular study of GCH-1 gene showed the Q89X mutation in exon 1. Treatment with l-dopa resulted in a complete remission of symptoms.
Asunto(s)
Antiparkinsonianos/efectos adversos , GTP Ciclohidrolasa/deficiencia , Hipocinesia/inducido químicamente , Levodopa/efectos adversos , Rigidez Muscular , Salud de la Familia , Femenino , Humanos , Hipocinesia/fisiopatología , Lactante , Masculino , Estudios RetrospectivosRESUMEN
OBJECTIVES: To evaluate the usefulness of Phe loading test in patients for the diagnosis of guanosine triphosphate cyclohydrolase 1 deficiency (GTPCH). DESIGN AND METHODS: We studied one family composed of 13 members harbouring the Q89X mutation in the GTPCH gene, a non-related pediatric patient with GTPCH deficiency and 8 pediatric controls. 100 mg/kg of L-phenylalanine was orally administered, and blood spot samples were taken at baselines 1, 2, 4 and 6 h post-load. RESULTS: Two out of 7 pediatric patients showed a phenylalanine/tyrosine ratio higher than the previously reported cut-off value of 5.25 at 4 h, while 6 of the 7 adult patients showed a higher value. The only adult patient with a phenylalanine/tyrosine ratio below 5.25 at 4 h was asymptomatic. CONCLUSIONS: A cut-off value of 5.25 seems reliable for interpreting Phe loading test in adult patients with GTPCH deficiency, although a lower value should be established for pediatric patients.