Mutations in the GBA gene are numerically the most important risk factor for developing Parkinson disease (PD) accounting for at least 5% of all PD cases [108], while mutations in the LRKK2 gene were found in 0.5% to 2.0% of sporadic PD and 5% of dominantly inherited familial parkinsonism [109]. The gene discussed is GBA1; the disease is Parkinson disease.