Gene: TH1-4

Enzyme: Tyrosine-3-hydroxylase (EC 1.14.16.2)

Reaction: Tyr > (+O₂ + BH₄) > L-Dopa

DD: 1) Severe early onset TH def.; 2) Mild late onset TH def. (DRD)

Diagnosis: CSF; Blood; DNA
CSF: 5HIAA (n); HVA (low), MHPG (low)
Plasma: Prolactin (high)
DNA: see PNDDB

Clinical signs & symptoms:
Parkinsonism-dystonia
Truncal hypotonia
Chorea/athetosis
Ptosis
Tremor
Hypokinesia

Treatment:
L-Dopa/Carbidopa (10 or 25%) - 1-10 mg/kg/d - 2-6 doses/day

Alternative treatment:
Selegiline 0.1-0.3 mg/kg/d - 2-3 doses/day
Entacapone 30 mg/kg/d - 2 doses/day
Bromocriptine 0.25-0.5 mg/kg/d - 1 dose/day