Author Affiliations: Division of Epidemiology, Department of Health Sciences Research, and Department of Neurology, College of Medicine, Mayo Clinic, Rochester, Minnesota.
We are reaching the convergence of 2 important lines of research on the etiology of Parkinson disease (PD). The first line involves the accumulation of evidence on the familial aggregation of multiple neurodegenerative diseases, including PD. The second line involves the accumulation of evidence on the association of PD with a decreased risk of some types of cancer and an increased risk of some other types of cancer, primarily melanoma.
Along the first line of research, first-degree relatives of patients with younger-onset PD were found to have an increased risk not only of PD or parkinsonism but also of essential tremor, cognitive impairment or dementia, anxiety disorders, and depressive disorders, compared with relatives of controls.1- 3 A reciprocal familial aggregation of other neurodegenerative disorders, including PD, was also found among relatives of patients with amyotrophic lateral sclerosis or with dementia.4,5 These studies suggest that some genetic or environmental factors may cluster in some families and may cause several distinct neurologic or psychiatric diseases.
Rocca WA. Families With Parkinson Disease and Cancer. Arch Neurol. 2012;69(12):1549-1550. doi:10.1001/archneurol.2012.2664