We did not find an association of oligodendrocytes with Parkinsonism for genes affected by rare variants. This result may reflect etiological differences between sporadic and familial forms of the disease or the low power and insufficient number of genes tested. Prior evidence has suggested an involvement of oligodendrocytes in Parkinson’s disease. For example, α-synuclein-containing inclusions have been reported in oligodendrocytes in Parkinson’s disease brains 71. These inclusions (“coiled bodies”) are typically found throughout the brainstem nuclei and fiber tracts 72. Although the presence of coiled bodies in oligodendrocytes is a common, specific, and well-documented neuropathological feature of Parkinson’s disease, the importance of this cell type and its early involvement in disease has not been fully recognized. Our findings suggest that intrinsic genetic alterations in oligodendrocytes occur at an early stage of disease, which precedes the emergence of neurodegeneration in the substantia nigra, arguing for a key role of this cell type in Parkinson’s disease etiology.
