LRRK2 and Parkinson disease: While the etiology of PD is not fully understood [10], approximately 5–10% of cases have a genetic basis, with mutations in genes such as SNCA (encoding α-syn), DJ-1, PINK1, and LRRK2 leading to early-onset forms of the disease; however, the majority of PD cases are idiopathic and age-associated [11,12].