Table 2.

Treatable metabolic disorders that may evoke tremor^57–59

Metabolic disorder	Movement disorders	Laboratory tests	Gene
Wilson disease	Dystonia, parkinsonism, ataxia, chorea, tremor	Serum ceruloplasmin, 24 hours urinary copper excretion	ATP7B
Niemann-Pick type C	Ataxia, dystonia, rarely tremor	Oxysterols, chitotriosidase	NPC1, NPC2
Glutaric aciduria type 1	Dystonia, parkinsonism, chorea, rarely tremor	Plasma+urine organic acids, plasma acylcarnitines	GCDH
Ataxia with vitamin E deficiency	Ataxia, dystonia, rarely tremor	Plasma vitamin E level	TTPA
Segawa disease (DRD)	Dystonia, parkinsonism, tremor	CSF dopamine levels	GCH1
Coenzyme Q10 deficiency	Ataxia, dystonia, tremor, spasticity	Serum lactate, biochemical activities of respiratory chain complexes in skin or muscle, muscle CoQ10 level	Multiple genes

CSF, cerebrospinal fluid; DRD, dopa-responsive dystonia.