CSF1R and Hereditary diffuse leukoencephalopathy with axonal spheroids and pigmented glia: Recently, Riku et al. reported pathological findings in an asymptomatic carrier of the causative gene, CSF1R; this patient did not present any clinical presentations of HDLS at that time but exhibited the same pathological features as those seen in a patient with HDLS.16 In addition, some reports described abnormal conventional brain MRI findings in carriers even before HDLS development.3,17 Brain metabolism might be altered in asymptomatic carriers; however, to our knowledge, no MRS alteration has been reported in this population.18