Since our description of a patient with leukoencephalopathy and highly elevated polyols in the brain and body fluids, we started screening for polyol abnormalities in patients highly suspected of a metabolic disorder. We identified four additional patients with consistent abnormalities in sugar and polyol profiles in body fluids. The clinical, neuroimaging, and biochemical findings of the five patients detected so far are described in the present paper. In four patients neurological problems dominated the clinical picture, whereas liver failure dominated in the other patient. The sugar and polyol profiles were abnormal in body fluids in all patients, but the profiles were different in individual patients. A deficiency of transaldolase was found in the patient presenting with liver failure. We were not able to identify the basic defect in the four patients with predominantly neurological problems. The differences in clinical picture, MRI abnormalities, and sugar and polyol profiles in these patients suggest that the underlying defects may be different. Whether the abnormal sugar and polyol profiles are directly related to the cause of disease via defects in polyol metabolism or transport remains to be elucidated.