Although most PD cases are idiopathic, about 5–10% of them are hereditary and are attributed to autosomal recessive (such as parkin/PARK2 and PINK1/PARK6) or autosomal dominant (such as LRRK2, SNCA, VPS35) mutations (Deng et al., 2018). The gene discussed is SNCA; the disease is Parkinson disease.