摘要
Most patients with idiopathic REM sleep behavior disorder (IRBD) are diagnosed with the synucleinopathies Parkinson disease (PD) and dementia with Lewy bodies. Conversion rates have been estimated to be 35% at 5 years, 73% at 10 years, and 92% at 14 years after IRBD diagnosis.(1) Accordingly, IRBD is considered as a marker of the prodromal stage of synucleinopathies. In PD, RBD occurs in about 50% of the patients and in 18% of them, RBD symptoms precede the onset of parkinsonism.(2) Most cases of PD are sporadic, but approximately 5% to 10% of cases encompass monogenic forms caused by mutations in PD-associated genes. Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene represent the most common genetic cause of both familial PD and sporadic PD (sPD). Indeed, the G2019S mutation has been detected in up to 6% of familial and 3% of sPD cases in Europeans.(3) Moreover, the LRRK2-associated PD form (LRRK2-PD) is clinical and neuropathologically similar to sPD lacking LRRK2 mutations.(3</SUP)