The cerebellar ataxia syndromes are a heterogeneous group of disorders clinically characterized by the presence of cerebellar dysfunction. Initial assessment of patients with progressive cerebellar ataxia is complex because of an extensive list of potential diagnoses. A detailed history and comprehensive examination are required for an accurate diagnosis and hierarchical diagnostic investigations. Although no cure exists for most of these conditions, a small group of metabolic, hereditary, inflammatory, and immune-mediated etiologies of cerebellar ataxia are amenable to disease-modifying, targeted therapies. Over the past years, disease-specific treatments have emerged. Thus, clinicians must become familiar with these disorders because maximal therapeutic benefit is only possible when done early. In this article, we review disorders in which cerebellar ataxia is a prominent clinical feature requiring targeted treatments along with specific management recommendations.

Background and ObjectivesGenetic variants affect both Parkinson disease (PD) risk and manifestations. Although genetic information is of potential interest to patients and clinicians, genetic testing is rarely performed during routine PD clinical care. The goal of this study was to examine interest in comprehensive genetic testing among patients with PD and document reactions to possible findings from genome sequencing in 2 academic movement disorder clinics.MethodsIn 203 subjects with PD (age = 63 years, 67% male), genome sequencing was performed and filtered using a custom panel, including 49 genes associated with PD, parkinsonism, or related disorders, as well as a 90-variant PD genetic risk score. Based on the results, 231 patients (age = 67 years, 63% male) were surveyed on interest in genetic testing and responses to vignettes covering (1) familial risk of PD (LRRK2); (2) risk of PD dementia (GBA); (3) PD genetic risk score; and (4) secondary, medically actionable variants (BRCA1).ResultsGenome sequencing revealed a LRRK2 variant in 3% and a GBA risk variant in 10% of our clinical sample. The genetic risk score was normally distributed, identifying 41 subjects with a high risk of PD. Medically actionable findings were discovered in 2 subjects (1%). In our survey, the majority (82%) responded that they would share a LRRK2 variant with relatives. Most registered unchanged or increased interest in testing when confronted with a potential risk for dementia or medically actionable findings, and most (75%) expressed interest in learning their PD genetic risk score.DiscussionOur results highlight broad interest in comprehensive genetic testing among patients with PD and may facilitate integration of genome sequencing in clinical practice.