In the scope of this study, we have not evaluated the salivary DJ-1 levels in other parkinsonian disorders whose symptoms may overlap with sporadic PD clinically, such as ET, PSP, and MSA, etc. Further studies with disease control for important confounding factors are necessary to determine whether salivary DJ-1 could differentiate PD from those related disorders. The gene discussed is PARK7; the disease is parkinsonian disorder.