SPG11-related parkinsonism: Clinical profile, molecular imaging and l-dopa response.

<bold>Background: </bold>Molecular imaging has proven to be a powerful tool to elucidate degenerated paths in a wide variety of neurological diseases and has not been systematically studied in hereditary spastic paraplegias.<bold>Objectives: </bold>To investigate dopaminergic degeneration in a cohort of 22 patients with hereditary spastic paraplegia attributed to SPG11 mutations and evaluate treatment response to l-dopa.<bold>Methods: </bold>Patients and controls underwent single-photon emission computed tomography imaging utilizing 99m Tc-TRODAT-1 tracer. A single-blind trial with 600 mg of l-dopa was performed comparing UPDRS scores.<bold>Results: </bold>Reduced dopamine transporter density was universal among patients. Nigral degeneration was symmetrical and correlated with disease duration and motor and cognitive handicap. No statistically significant benefit could be demonstrated with l-dopa intake during the trial.<bold>Conclusion: </bold>Disruption of presynaptic dopaminergic pathways is a widespread phenomenon in patients with SPG11 mutations, even in the absence of parkinsonism. Unresponsiveness to treatment could be related to postsynaptic damage that needs to be further investigated. [ABSTRACT FROM AUTHOR]