Figure 1.

Potential causal relationships between Parkinson disease and uric acid. The commonly held viewpoint is that low uric acid leads to increased oxidative stress, which in turn contributes to dopamine neuron degeneration that triggers initial appearance of symptoms and contributes to progression. However, the direction of causation may be the opposite; Parkinson disease may cause low uric acid. Some potential mechanisms for reverse causation may include mitochondrial dysfunction, inherently low purine metabolism, dietary habits, changes in gastrointestinal motility or microbiome, or low physical activity.