Parkinsonian features in hereditary diffuse leukoencephalopathy with spheroids (HDLS) and CSF1R mutations

Abstract

Atypical Parkinsonism associated with white matter pathology has been described in cerebrovascular diseases, mitochondrial cytopathies, osmotic demyelinating disorders, leukoencephalopathies leukodystrophies, and others. Hereditary diffuse leukoencephalopathy with spheroids (HDLS) is an autosomal dominant disorder with symptomatic onset in midlife and death within a few years after symptom onset. Neuroimaging reveals cerebral white matter lesions that are pathologically characterized by non-inflammatory myelin loss, reactive astrocytosis, and axonal spheroids. Most cases are caused by mutations in the colony-stimulating factor 1 receptor (CSF1R) gene. We studied neuropathologically verified HDLS patients with CSF1R mutations to assess parkinsonian features. Ten families were evaluated with 16 affected individuals. During the course of the illness, all patients had at least some degree of bradykinesia. Fifteen patients had postural instability, and seven had rigidity. Two patients initially presented with parkinsonian gait and asymmetrical bradykinesia. These two patients and two others exhibited bradykinesia, rigidity, postural instability, and tremor (two with resting) early in the course of the illness. Levodopa/carbidopa therapy in these four patients provided no benefit, and the remaining 12 patients were not treated. The mean age of onset for all patients was about 45 years (range, 18-71) and the mean disease duration was approximately six years (range, 3-11). We also reviewed HDLS patients published prior to the CSF1R discovery for the presence of parkinsonian features. Out of 50 patients, 37 had gait impairments, 8 rigidity, 7 bradykinesia, and 5 resting tremor. Our report emphasizes the presence of atypical Parkinsonism in HDLS due to CSF1R mutations.

Keywords: Autosomal dominant; CSF1R mutation; HDLS; Parkinsonism; White matter disorders.

Figure 1

MRI (A-C) and neuropathology (D-F) of HDLS cases with CSF1R mutations A, B) Axial FLAIR MRI images; C) Axial T2-weighted MRI image. A) Localized, periventricular, deep, and subcortical white matter lesions (WML), more severe on the left side (arrows). B) Bilateral frontoparietal WML involving periventricular, deep, and subcortical areas with U-fiber sparing (arrows). C) Involvement of the corticospinal tracts bilaterally (arrows) at the level of the mesencephalon. D, E) Luxol fast blue; F) Hematoxylin-eosin. D) Myelin loss in the white matter of the superior frontal lobe. E) Tissue vacuolation with axonal spheroids (arrow) (magnification: ×400). F) The ventrolateral part of substantia nigra has minimal focal neuronal loss with extraneuronal neuromelanin (magnification: ×100).