Nonmotor symptoms in sporadic versus familial forms of Parkinson's disease

Besides the classical motor symptoms, Parkinson's disease (PD) patients experience a wide range of nonmotor symptoms (NMS) throughout the disease course. However, due to the lack of recognition and understanding of the pathogenesis, NMS symptoms may be overlooked. Familial PD is a well-defined group that can provide a good model to investigate the mechanisms for both motor and NMS in PD. Some studies suggest that the frequency of NMS is not different between genetic and sporadic form of PD while others suggest that specific domains (such as neuropsychiatric symptoms) are more common in the genetic form. Early recognition of NMS may facilitate early diagnosis and monitoring of both sporadic and genetic PD.