CLINICS 2010;65(11):1217-1218 LETTER TO THE EDITOR DOI:10.1590/S1807-59322010001100028 Cerebrotendinous xanthomatosis: a treatable hereditary neuro-metabolic disease Ana Claudia Rodrigues de Cerqueira,I Antoˆ nio Egı´dio Nardi,I Jose Marcelo Ferreira BezerraII I Instituto de Psiquiatria, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. II Departamento de Neurologia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil. Email: anacerqueira@globo.com Tel.: 55 21 2521-6147 INTRODUCTION Cerebrotendinous xanthomatosis is a rare autosomal recessive hereditary disease that is caused by a mutation in the gene encoding the mitochondrial enzyme sterol 27- hydroxylase (CYP27). The CYP27 gene is located on chromosome 2q35-qter and is responsible for the conversion of cholesterol into cholic and chenodeoxycholic acid. Cerebrotendinous xanthomatosis results in increased levels of serum cholestanol, a cholesterol precursor, and increased deposition of cholestanol and cholesterol in various tissues, especially the lenses, tendons, and the central nervous system. The principal manifestations of Cerebrotendinous xanthomatosis include juvenile cataracts, tendon xantho- mas, and progressive neurological symptoms.1 Early recognition of this condition is essential because cholic and chenodeoxycholic acid replacement therapy can prevent Cerebrotendinous xanthomatosis -induced brain damage, which leads to severe neurological dysfunction and death. We present the case of a patient with clinical, radiological, and biochemical evidence of Cerebrotendinous xanthomatosis and his response to cholic and chenodeoxy- cholic acid treatment. CASE REPORT This report describes a 30-year-old male who displayed normal psychomotor development until 10 years of age when, according to his mother, he began presenting learning difficulties and showed progressive cognitive decline. At 15 years of age, the patient presented progres- sive gait instability and enlargement of the Achilles tendons. At age 17, he suffered his first convulsive episode. The patient has suffered a total of four seizures since that time, and his seizure condition is adequately controlled with the use of anticonvulsants. A family history revealed that the patient’s parents were cousins. Physical examination revealed bilateral Achilles tendon enlargement and bilateral cataracts. A neurological examination identified spastic paraparesis, brisk deep tendon reflexes and extensor plantar responses, upper limb symmetrical dysmetria and dysdia- dochokinesia, and ataxic-paraparetic gait. The remainder of the patient’s physical examination was normal. Copyright 2010 CLINICS – This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non- commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Magnetic resonance imaging (MRI) of the patient’s skull revealed mild cerebellar atrophy (Figure 1). MRI of the left ankle showed fusiform thickening of the Achilles tendon with heterogeneous signals on all sequences, T2-hyperin- tense foci due to the presence of fat, and a slight increase in the uptake of paramagnetic contrast. These results were suggestive of a xanthoma of the Achilles tendon (Figure 2). Laboratory tests (complete blood count, biochemistry, liver and kidney function, lipid panel, and coagulation tests) were normal. The patient’s serum cholestanol level was high (28.3 mg/mL, normal value ,6 mg/mL). Based on these findings, the patient was diagnosed with CTX, and treatment with CDCA (750 mg/day) was imme- diately initiated. The drug was imported from Germany. A significant improvement in neurological symptoms was observed after one year of follow-up, especially with respect to ataxia and coordination. The patient retains a slightly ataxic gait but presents normal finger-to-nose and fast finger movements, and his serum cholestanol level has been reduced to 4.1 mg/mL. In addition, the patient has under- gone eye surgery to treat his cataracts. The patient authorized the publication of this case report by signing a consent form. DISCUSSION Van Bogaert et al. described the first CTX phenotype in 1937.2 Subsequent work established several additional symptoms of CTX, including cholestanol accumulation in 1217 Figure 1 - Brain MRI sagittal section in T1, showing mild cerebellar atrophy in a patient with CTX.