Abstract: Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a rare autosomal-dominant progressive leukodystrophy, caused by mutations of colony stimulating factor-1 receptor (CSF1R) gene. Age of onset is usually between 40 and 50 years old and the clinical presentations include dementia, apraxia, behavioral changes, pyramidal and extrapyramidal signs. Varying clinical manifestations have led to misdiagnoses. Magnetic resonance imaging (MRI) typically reveals white matter changes with T2-Flair/DWI hyperintensity and atrophy especially for thinning of the corpus callosum. Here, we report a young woman experiencing hypomnesia for 2 years with lower extremities weakness and rigidity for 1 month. Considering the evidence of clinical manifestations, imaging and genetic test, this patient was diagnosed with ALSP.