A 43-year-old female with personality changes and alien limb

Colony stimulating factor-1 receptor <i>(CSF1R)</i> encodes for a tyrosine kinase receptor expressed on microglia. <i>CSF1R</i> related disorder is a devastating autosomal dominant leukoencephalopathy caused by <i>CSF1R</i> with variable penetrance in adults. It remains significantly underdiagnosed or misdiagnosed. We report a case of a 43-year-old woman with an insidious onset of neurocognitive decline, alien limb phenomenon, and personality changes over 1 year. In this report we will discuss the clinical approach, differential diagnosis, investigation, and available treatment options for <i>CSF1R</i> related disorder.