Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
Sign up to receive an email alert when a new Case of the Week is posted.
May 29, 2014
Cerebrotendinous Xanthomatosis
- Cerebrotendinous xanthomatosis (CTX) is a rare autosomal-recessive lipid storage disease. The primary enzymatic defect is in the mitochondrial enzyme sterol 27-hydroxylase, which leads to the accumulation of β-cholestanol in different tissues, preferably by tendons, crystalline structures, and the central nervous system.
- Characterized by abnormal bile acid synthesis. There is decreased production of chenodeoxycholic acid (CDCA). This in turn causes increased cholesterol and cholestanol. High bile alcohols in urine or plasma cholestanol levels are diagnostic.
- Clinical Presentation: There are 2 forms of CTX: classic and spinal. The classic form has cerebellar involvement, dementia, tendon xanthoma formation, and peripheral neuropathy, leading to death between 30 and 40 years of age. The rare, milder “spinal” form (case 2) demonstrates extensive white matter lesions in the lateral corticospinal tracts and in the gracile tracts.
- Key Diagnostic Features: Bilateral xanthomas of the achilles tendons, bilateral incresed signal in cerebellum dentate nucleus, in a young man with juvenile cataracts, chronic diarrea, and neurological simptoms. The “spinal form” has been sparsely described in the literature. Reported cases demonstrate spinal cord atrophy and T2-weighted signal abnormalities in the lateral tracts and posterior columns.
- DDx: Classic: Disorders associated with xanthomas, such as sitosterolemia, hypercholesterolemia, and hyperlipemia (especially type IIa). On imaging there is no brain involvement. Clinically, CTX resembles Marinesco-Sjögren syndrome. The presence of tendon xanthomas helps differentiate CTX from this condition. Spinal: Subacute combined degeneration, multiple sclerosis, and HIV myelitis.
- Rx: Conservative management with ursodeoxycholic acid and HMG-CoA reductase inhibitors. Baclofen to aid spasticity. Lipid lowering agents such as simvastatin. Alternatively, administration of CDCA has shown success in low-powered trials.