Electromyography, nerve conduction studies, and serum and urinary amino acid analysis were unremarkable. Analysis of CSF revealed mild elevation of IgG (7.5 mg/dL). Bone marrow examination was inconclusive. Activities of sphingomyelinase and hexosaminidase were within normal limits. Abdominal ultrasonography was negative for hepatosplenomegaly, as it was during check details the

entire course of the illness. By the age of 14 years, the patient had become tetraparetic. A gastrostomy tube was placed because of increasing dysphagia at 16 years of age. He subsequently became bedridden with total dependence. At age 22, a tracheostomy was performed and respiratory mTOR inhibitor support with mechanical ventilation was started. Brain MRI performed at 31 years of age revealed marked brain atrophy, especially in the frontotemporal lobes, hippocampus, brainstem and cerebellum (Fig. 1). In contrast to severe involvement of the frontotemporal region, the parieto-occipital region was relatively spared

(Fig. 1). Seizures were well-controlled by phenobarbital and carbamazepine, and no apparent episodes occurred during the last 12 years of his life. The last EEG was performed at age 31 and showed no epileptic discharge. He died from acute pancreatitis at age 37 years. The clinical diagnosis at the time of death was unclassified neurodegenerative disease of childhood onset.

An autopsy was performed Ribose-5-phosphate isomerase 3 h after death. All organs were fixed with 10% phosphate-buffered formalin. Paraffin-embedded tissue blocks were cut into 6 μm sections, which were then stained with HE. CNS tissue sections were subjected to KB staining. The Gallyas-Braak silver stain and immunohistochemistry were performed on selected CNS sections. For filipin staining, liver tissue was embedded in O.C.T. compound (Sakura Finetechnical Co., Tokyo, Japan) and cryosections of 10 μm thickness were cut using a Bright OTF Cryostat (Bright Instrument Co. Ltd, Huntingdon, UK). Sections were immersed in 10% phosphate-buffered formalin for 10 min at 4°C, washed with distilled water three times, and incubated with 0.1 mg/mL filipin III (Cayman Chemical, Ann Arbor, MI, USA) for 1 h at room temperature in the dark. After rinsing in PBS, sections were coverslipped using a SlowFade Antifade kit (Invitrogen Life Technologies Corp., Carlsbad, CA, USA) and fluorescent images were acquired using a fluorescent microscope (Axiovert 200 M, Carl Zeiss Co. Ltd, Oberkochen, Germany).