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Locus: 14q22.1-22.2 |
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Gene: GCH1 |
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Reaction: GTP >> Dihydroneopterin triphosphate + Formiate |
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DD: arGTPCH deficiency (hyper-Phe) |
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Diagnosis: CSF, FB, DNA
CSF: Neo (low), Bio (low), 5HIAA (normal), HVA (low)
Phe Loading test (abnormal)
FB: GTPCH activty (low)
DNA: see PNDDB
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Clinical signs & symptoms:
Dystonia of lower limbs, trunk, arms, neck
Diurnal fluctuations of symptoms
Parkinsonism (adulthood)
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Treatment:
L-Dopa/Carbidopa (10 or 25%) <12 mg/kg/d - 3-4 doses/day
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Alternative treatment:
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