-related adult-onset leukoencephalopathy with axonal spheroids: A case series of four Asian Indian patients.

Background: Colony stimulating factor 1 receptor-related leukoencephalopathy (CSF1R-L) is a rare, adult onset leukoencephalopathy. Descriptions from the Indian subcontinent remain limited.

Objective: To report four patients with genetically confirmed CSF1R-L from four Asian Indian families, describing clinical, molecular and radiological features.

Methods: All patients underwent clinical examination, MRI brain, and whole exome sequencing to identify causative variants in CSF1R gene. We also reviewed published Indian cases with CSF1R-L.

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

Conclusions: We expand the literature from India with four new cases of CSF1R-L.