BACKGROUND Several pathogenic mutations in the LRRK2 gene have been implicated in familial and sporadic cases of Parkinson disease (PD). The R1441G mutation is frequent in Spanish patients of Basque ethnicity with PD, and the G2019S mutation is a common mutation found in several populations worldwide. OBJECTIVES To determine the frequency of the LRRK2 G2019S and R1441G mutations in PD patients from the non-Basque northeast region of Spain (Catalonia), and to characterize their family history and clinical features. DESIGN We screened patients for the presence of the LRRK2 R1441G and G2019S mutations. These LRRK2 mutations were detected by restriction endonuclease digestion, and samples with an abnormal electrophoresis pattern were sequenced to identify the exact nucleotide change. The clinical features and family history of patients with LRRK2 mutations were studied in detail. SETTING The northeast region of Spain. Patients Three hundred two patients with PD. MAIN OUTCOME MEASURES Onset age, clinical features, and family history of PD and LRRK2 mutations. RESULTS The R1441G mutation was present in 0.7% of total PD cases. The G2019S mutation was found in 6.4% of familial and 3.4% of sporadic cases. Additionally, we found 1 patient with the R1441C mutation. Age at onset ranged from 33 to 78 years. Clinical features were not different from classic PD, except for 1 patient who presented with monosymptomatic leg rest tremor of 8 years' duration. In addition, a 91-year-old unaffected relative of a patient with the G2019S mutation was found to be a mutation carrier. CONCLUSIONS The G2019S mutation frequency in PD patients from northeast Spain is similar to that reported in other European regions. The R1441G mutation is very uncommon in Catalonia. The presence of an aged unaffected G2019S mutation carrier supports the previously described occurrence of incomplete penetrance in PD patients with LRRK2 mutations.