Primary progressive multiple sclerosis developing in the context of young onset Parkinson's disease.

We report a patient with young onset Parkinson's disease (PD) and a heterozygous point mutation in parkin (c.1000C>T; p.Arg334Cys). After 8 years he developed pyramidal signs and reinvestigation demonstrated MRI and laboratory findings supportive of a diagnosis of multiple sclerosis (MS) with a primary progressive (PP) clinical course. This is a previously un-described association of young onset PD with PPMS. Imaging clearly dates the occurrence of each disease as chronologically separate phenomena. There is not currently evidence for shared causation or pathogenesis between the two neurological disorders but we will follow with interest the emerging genetic characterization of parkin in both PD and MS.