A novel PLP1 mutation F240L identified in a patient with connatal type Pelizaeus-Merzbacher disease

Terra incognita of glial cell dynamics in the etiology of leukodystrophies: Broadening disease and therapeutic perspectives

Neuroglial cells, also known as glia, are primarily characterized as auxiliary cells within the central nervous system (CNS). The recent findings have shed light on their significance in numerous physiological processes and their involvement in various neurological disorders. Leukodystrophies encompass an array of rare and hereditary neurodegenerative conditions that were initially characterized by the deficiency, aberration, or degradation of myelin sheath within CNS. The primary cellular populations that experience significant alterations are astrocytes, oligodendrocytes and microglia. These glial cells are either structurally or metabolically impaired due to inherent cellular dysfunction. Alternatively, they may fall victim to the accumulation of harmful by-products resulting from metabolic disturbances. In either situation, the possible replacement of glial cells through the utilization of implanted tissue or stem cell-derived human neural or glial progenitor cells hold great promise as a therapeutic strategy for both the restoration of structural integrity through remyelination and the amelioration of metabolic deficiencies. Various emerging treatment strategies like stem cell therapy, ex-vivo gene therapy, infusion of adeno-associated virus vectors, emerging RNA-based therapies as well as long-term therapies have demonstrated success in pre-clinical studies and show promise for rapid clinical translation. Here, we addressed various leukodystrophies in a comprehensive and detailed manner as well as provide prospective therapeutic interventions that are being considered for clinical trials. Further, we aim to emphasize the crucial role of different glial cells in the pathogenesis of leukodystrophies. By doing so, we hope to advance our understanding of the disease, elucidate underlying mechanisms, and facilitate the development of potential treatment interventions.

Overview of Neuro-Ophthalmic Findings in Leukodystrophies

Background: Leukodystrophies are a group of rare genetic diseases that primarily affect the white matter of the central nervous system. The broad spectrum of metabolic and pathological causes leads to manifestations at any age, most often in childhood and adolescence, and a variety of symptoms. Leukodystrophies are usually progressive, resulting in severe disabilities and premature death. Progressive visual impairment is a common symptom. Currently, no overview of the manifold neuro-ophthalmologic manifestations and visual impact of leukodystrophies exists. Methods: Data from 217 patients in the Hamburg leukodystrophy cohort were analyzed retrospectively for neuro-ophthalmologic manifestations, age of disease onset, and magnetic resonance imaging, visual evoked potential, and optical coherence tomography findings and were compared with data from the literature. Results: In total, 68% of the patients suffered from neuro-ophthalmologic symptoms, such as optic atrophy, visual neglect, strabismus, and nystagmus. Depending on the type of leukodystrophy, neuro-ophthalmologic symptoms occurred early or late during the course of the disease. Magnetic resonance imaging scans revealed pathologic alterations in the visual tract that were temporally correlated with symptoms. Conclusions: The first optical coherence tomography findings in Krabbe disease and metachromatic leukodystrophy allow retinal assessments. Comprehensive literature research supports the results of this first overview of neuro-ophthalmologic findings in leukodystrophies.

Glial cells in the driver seat of leukodystrophy pathogenesis

Glia cells are often viewed as support cells in the central nervous system, but recent discoveries highlight their importance in physiological functions and in neurological diseases. Central to this are leukodystrophies, a group of progressive, neurogenetic disease affecting white matter pathology. In this review, we take a closer look at multiple leukodystrophies, classified based on the primary glial cell type that is affected. While white matter diseases involve oligodendrocyte and myelin loss, we discuss how astrocytes and microglia are affected and impinge on oligodendrocyte, myelin and axonal pathology. We provide an overview of the leukodystrophies covering their hallmark features, clinical phenotypes, diverse molecular pathways, and potential therapeutics for clinical trials. Glial cells are gaining momentum as cellular therapeutic targets for treatment of demyelinating diseases such as leukodystrophies, currently with no treatment options. Here, we bring the much needed attention to role of glia in leukodystrophies, an integral step towards furthering disease comprehension, understanding mechanisms and developing future therapeutics.