CSF1R-Related Adult-Onset Leukoencephalopathy With Axonal Spheroids: A Case Series of Four Asian Indian Patients.

Objective: Colony-stimulating factor 1 receptor-related leukoencephalopathy (CSF1R-L) is a rare adult-onset leukoencephalopathy. Reports of CSF1R-L patients from the Indian subcontinent remain limited. We aimed to report four patients with genetically confirmed CSF1R-L from four Asian Indian families and described their clinical, molecular, and radiological features.

Methods: All patients underwent clinical examination, brain magnetic resonance imaging, and whole-exome sequencing to identify causative variants in the CSF1R gene. We also reviewed published reports of Indian patients with CSF1R-L.

Results: The age at enrollment ranged from 34 to 40 years. The duration of symptoms ranged from 11 months to 2 years. The chief clinical phenotype in three patients was a rapidly evolving cognitive-behavioral syndrome combined with atypical parkinsonism, and asymmetrical spastic tetraparesis was observed in one patient. We identified four different variants (three missense variants and one in-frame deletion). Radiological findings revealed white matter involvement and diffusion restriction involving the subcortical white matter and pyramidal tracts.

Conclusion: We expand the literature on CSF1R-L patients from India by reporting four new cases.