LRRK2 and Parkinson disease: Lower levels of purine nucleotide intermediates are especially notable in the context of PD; the plasma of PD patients (both LRRK2 mutant-associated and idiopathic) has been shown to contain significantly less hypoxanthine and uric acid (Johansen et al., 2009), and patients with higher plasma urate levels, despite carrying LRRK2 mutations, are less likely to develop PD (Bakshi et al., 2019).