[Cerebrotendinous xanthomatosis without tendinous xanthomas: presentation of two cases].

Cerebrotendinous xanthomatosis (CTX) is a genetic disorder caused by a 27-hydroxilase enzyme deficiency, leading to beta-cholestanol storage in many body tissues. Clinically, the disease is characterised by the presence of tendinous xanthomas, juvenile cataracts and progressive neurologic dysfunction. The diagnosis requires beta-cholestanol quantification in serum. We report two siblings with a history of photosensitive epilepsy of childhood onset, who developed progressive spastic paraparesis and cataracts in their third decade of life. They were diagnosed to have CTX in spite of the absence of tendinous xanthomas. Cranial and spinal MRI only showed bilateral high intensity signal in the dentate nuclei in the T2-weighted and proton-density sequences. Our patients presented with a progressive spastic paraparesis. The delay in the diagnosis in our case could be due to the absence of tendinous xanthomas and late-onset cataracts. The recognition of the disease is important, because the treatment with chenodeoxycholic acid induces a decrement of beta-cholestanol levels in serum and could prevent the progression of the disease.