CSF1R and Hereditary diffuse leukoencephalopathy with axonal spheroids and pigmented glia: Mutations in the CSF1R (colony stimulating factor-1 receptor) gene are known to cause an adult-onset leukodystrophy termed hereditary diffuse leukoencephalopathy with spheroids (HDLS).21 This condition has been shown to be one of the most common causes of adult-onset leukodystrophy, accounting for approximately 10% of cases.22 First described in a large Swedish kindred,23 this is an autosomal dominant disorder in which affected members develop a clinical course characterised by dementia, psychiatric changes and motor decline.