Sporadic Japanese case of adult‐onset leukoencephalopathy with axonal spheroids and pigmented glia caused by a de novo p.Phe849del mutation in CSF1R

Abstract

Adult‐onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is an autosomal dominant neurodegenerative disorder caused by mutations in the colony‐stimulating factor 1 receptor (CSF1R) gene. We, herein, report the first Japanese case of ALSP caused by a de novo p.Phe849del mutation in CSF1R: a 44‐year‐old man who presented callosal disconnection symptoms. Brain MRI revealed dilation of the lateral ventricles, periventricular white matter hyperintensities, and thinning of the corpus callosum with hyperintensities on T2‐weighted and FLAIR images. Brain single photon emission computed tomography (SPECT) showed hypoperfusion in the anterior corpus callosum. White matter lesions in MRI and hypoperfusion in SPECT increased with age. A brain biopsy at 44 years revealed axonal spheroids. Callosal disconnection symptoms and hypoperfusion in the anterior corpus callosum may be important indicators of ALSP, especially when caused by a p.Phe849del CSF1R mutation.