Table 1.

Differential diagnosis of JPD, DRD, DRD-plus, and transportopathy

	JPD	DRD	DRD-plus	Transportopathy
				DAT deficiency	VMAT2 deficiency
Age of onset	Childhood~Adolescence	Childhood~Adolescence	Infancy	Infancy	Infancy
Symptoms and signs
Motor symptoms
Dystonia	+/−	+	+/−	+	+
Parkinsonism	+	+/−	+/−	+	+
Nonmotor symptoms	-	-	+	+	+
Systemic symptoms	-	-	+	+	+
Diurnal fluctuation	+/−	+	+/−	-	-
Laboratory tests
DAT imaging	Abnormal	Normal	N/Aa	Markedly abnormal	N/Aa
CSF NTs	Neopterin:	A/T subtypeb	A/T subtypeb	HVA/5-HIAA:	Normal
Urine NTs	N/Aa	A/T subtypeb	A/T subtypeb	HVA:	5-HIAA, HVA:
					NE, Dopamine:
Phenylalanine loading test	N/Aa	A/T subtypeb	A/T subtypeb	N/Aa	N/Aa
L-dopa responsec
Dose	Smalld	Small	Large	Large	No response
Response degree	Good	Marked	Partial	Partial	No responsee
Motor complicationsf	Frequentg	Absent	Presenth	Presenth	Presenth

^aIt is predicted to be normal.

^bAccording to subtype. Please refer to Supplement Table 1 for details.

^cDopa agonist is more effective than L-dopa in AADC deficiency, DAT deficiency and VMAT2 deficiency.

^dDose increases with time.

^eResponds to dopamine agonists.

^fMotor fluctuation and dyskinesias.

^gMotor complications occur as a late-complication.

^hDyskinesia may appear early by the administration of L-dopa in a dose-dependent manner.

5-HIAA hydroxyindoleacetic acid, AADC Aromatic L-amino acid decarboxylase, A/T According to, DAT dopamine transporter, DRD dopa-responsive dystonia, HVA homovanillic acid, JPD juvenile Parkinson’s disease, N/A not available, NE norepinephrine, NTs neurotransmitters, VMAT2 vesicular monoamine transporter 2