Our study is aimed at: 1) screening a cohort of PD patients in a restricted geographical area of Italy on the basis of simple clinical criteria by an extensive NGS gene panel, to implement diagnostic yield; 2) estimating the prevalence of GBA1 mutations and mendelian forms of PD in two movement disorders centers in North-Eastern Italy; 3) evaluating phenotypic features of patients with monogenic-PD. Here, GBA1 is linked to Parkinson disease.