Cerebrotendinous xanthomatosis. Report of one case Cerebrotendinous xanthomatosis (CTX) is an uncommon autosomal recessive disease caused by deficiency of 27-sterol-hydroxylase that results in an accumulation of cholestanol in the central nervous system, eyes, tendons, and blood vessels. We report a 22-year-old woman with a history of cataract surgery at the age of 14, cholecystectomy due to cholelithiasis at the age of 17 and chronic diarrhea, who presented with a six months period of gait instability and frequent falls. Physical examination revealed a bilateral pyramidal and cerebellar syndrome, with no visible tendon xanthomas. Cerebral magnetic resonance imaging showed an increase of the signal intensity on the T2-weighted images in periventricular cerebral white matter, dentate nuclei and spinal cord. With a high suspicion of CXT, a genetic study was conducted identifying a pathogenic variant in the CYP27A1 gene. There is considerable variation in clinical characteristics and age of onset of this disease, including absence of tendon xanthomas, delaying the diagnosis. Early recognition and chronic chenodeoxycholic acid therapy can improve outcome and quality of life.