Association Between Microbial Tyrosine Decarboxylase Gene and Levodopa Responsiveness in Patients With Parkinson Disease

BACKGROUND AND OBJECTIVES: is associated with levodopa responsiveness and could predict the drug response. METHODS: abundance in fecal samples were measured using quantitative real-time PCR. Plasma levodopa concentrations were measured using liquid chromatography-tandem mass spectrometry analysis. The predictive models for levodopa responsiveness were constructed and verified through cross-validation and external validation. RESULTS: gene abundance had good calibration and discrimination in cross-validation (C-index in training and test sets: 0.856 and 0.851, respectively) and external validation (C-index: 0.952). DISCUSSION: gene may provide new approaches for personalized levodopa treatment.