1/41. Mutations producing premature termination of translation and an amino acid substitution in the sterol 27-hydroxylase gene cause cerebrotendinous xanthomatosis associated with parkinsonism. OBJECTIVES: Mutational analysis of the sterol 27-hydroxylase (CYP27) gene was performed on three patients from two Japanese families who had cerebrotendinous xanthomatosis (CTX) associated with parkinsonism. methods: Clinical evaluations, brain MRI studies, and laboratory analyses were completed on the three patients. The CYP27 gene was analysed for mutations by PCR amplification of gene segments followed by direct sequencing. RESULTS: Two different, homozygous mutations were identified in these families. One is a novel transition, substituting T for G at Glu162 (GAG) resulting in a stop codon (TAG). The other is also a transition, substituting T for C at Arg441 (CGG) resulting in Trp (TGG). The second is located in two amino acids ahead of the heme ligand binding site (Cys443) of the protein likely rendering it non-functional. It is the most common CTX mutation in Japanese patients. CONCLUSIONS: CTX with parkinsonism is caused by mutations with a severe impact on enzyme function. The two mutations described here are likely to cause loss of function because they are chain terminating or affect an essential site in the protein. ( info) |
2/41. mutation of the sterol 27-hydroxylase gene (CYP27) results in truncation of mRNA expressed in leucocytes in a Japanese family with cerebrotendinous xanthomatosis. OBJECTIVES: A Japanese family with cerebrotendinous xanthomatosis (CTX) was investigated for a sequence alteration in the sterol 27-hydroxylase gene (CYP27). The expression of CYP27 has been mostly explored using cultured fibroblasts, prompting the examination of the transcripts from blood leucocytes as a simple and rapid technique. methods: An alteration in CYP27 of the proband was searched for by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis and subsequent sequencing. Samples of rna were subjected to reverse transcription PCR (RT-PCR) and the product of the proband was amplified with nested primers and sequenced. RESULTS: A homozygous G to A transition at the 5' end of intron 7 was detected in the patient. In RT-PCR analysis, only a truncated transcript was detected in the patient, whereas both normal and truncated transcripts were detected in the siblings. The sequencing of the patient's cDNA fragment disclosed a direct conjuction of exon 6 and exon 8. CONCLUSION: The mutation at splice donor site and the truncation of mRNA were identical with those of a recently reported Italian patient, although different in symptomatology. The application of blood leucocytes can be a simple technique on analysing a constructive abnormality of CYP27 mRNA. ( info) |
3/41. Sudden death due to cerebrotendinous xanthomatosis confirmed by mutation analysis. A case of sudden death of a 52-year-old mentally retarded Caucasian male is described where the rectal temperature was 43.4 degrees C 3 h postmortem. The autopsy revealed cerebrotendinous xanthomatosis (CTX), a rare hereditary metabolic disorder, as the primary disease. The diagnosis was confirmed by postmortem identification of two mutations (compound heterozygosity for R237X and IVS6 1G-->A) in the sterol 27-hydroxylase (CYP27) gene. Both mutations have already been described in patients with CTX and can be considered the most likely cause of the disease. The pathomechanism of the excessive hyperthermia could not be completely elucidated. ( info) |
4/41. MRI of the brain in cerebrotendinous xanthomatosis (van Bogaert-Scherer-Epstein disease). The clinical, biochemical and magnetic resonance imaging findings of two patients with cerebrotendinous xanthomatosis are reported. This is a rare hereditary disease. Early recognition of this entity is important in view of the existing treatment possibilities. magnetic resonance imaging findings typically include a bilateral and almost symmetrical increase of the signal intensity on the T2-weighted images in the cerebellar and periventricular cerebral white matter, the basal ganglia, the dentate nuclei and the brainstem as well as cerebellar and cerebral atrophy. ( info) |
5/41. Sterol 27-hydroxylase acts on 7-ketocholesterol in human atherosclerotic lesions and macrophages in culture. 27-Hydroxycholesterol (27OH) is the major oxysterol in human atherosclerotic lesions, followed by 7-ketocholesterol (7K). Whereas 7K probably originates nonenzymically, 27OH arises by the action of sterol 27-hydroxylase, a cytochrome P450 enzyme expressed at particularly high levels in the macrophage and proposed to represent an important pathway by which macrophages eliminate excess cholesterol. We hypothesized and here show that 27-hydroxylated 7-ketocholesterol (270H-7K) is present in human lesions, probably generated by the action of sterol 27-hydroxylase on 7K. Moreover, [(3)H]27OH-7K was produced by human monocyte-derived macrophages (HMDMs) supplied with [(3)H]7K but not in HMDMs from a patient with cerebrotendinous xanthomatosis (CTX) shown to have a splice-junction mutation of sterol 27-hydroxylase. Whereas [(3)H]27OH-7K was predominantly secreted into the medium, [(3)H]-27OH formed from [(3)H]-cholesterol was mostly cell-associated. The majority of supplied [(3)H]7K was metabolized beyond 27OH-7K to aqueous-soluble products (apparently bile acids derived from the sterol 27-hydroxylase pathway). metabolism to aqueous-soluble products was ablated by a sterol 27-hydroxylase inhibitor and absent in CTX cells. Sterol 27-hydroxylase therefore appears to represent an important pathway by which macrophages eliminate not only cholesterol but also oxysterols such as 7K. The fact that 7K (and cholesterol) still accumulates in lesions and foam cells indicates that this pathway may be perturbed in atherosclerosis and affords a new opportunity for the development of therapeutic strategies to regress atherosclerotic lesions. ( info) |
6/41. Diphenylpyraline-responsive parkinsonism in cerebrotendinous xanthomatosis: long-term follow up of three patients. A long-term follow-up study was made of three patients with cerebrotendinous xanthomatosis (CTX) associated with parkinsonism, two of whom were siblings. Besides typical CTX symptoms, all three patients showed severe parkinsonism. This observation has been rarely reported in CTX. The fact that the two siblings showed parkinsonism strongly suggests the genetic propensity to parkinsonism in these CTX patients. Positron emission tomography studies of the two patients revealed presynaptic dysfunction of the nigro-striatal dopaminergic system. Treatment with the reductase inhibitor hydroxymethyl glutaryl coenzyme successfully corrected the serum cholestanol level in the early stage of the disease, which, however, did not arrest the progression of clinical symptoms, particularly their parkinsonism. Clinically, levodopa had a little effect on parkinsonism, whereas an antihistamine drug, diphenylpyraline hydrochloride (DPP) had excellent effects on all three patients throughout the long-term follow up. The mechanism of the action of DPP on parkinsonism is unclear, however, the drug seems to be a therapeutic choice for treating parkinsonism in CTX. ( info) |
7/41. Clinical and biochemical features, molecular diagnosis and long-term management of a case of cerebrotendinous xanthomatosis. Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive sterol storage disease characterised clinically by juvenile bilateral cataracts, progressive neurological dysfunction, and formation of tendon xanthomata. We describe the clinical and biochemical features, molecular diagnosis and long-term management of the first reported Australasian case of CTX. Molecular analysis confirmed the diagnosis of CTX and demonstrated that the patient was homozygous for a G-->A transition in the splice donor site of intron 4 of the sterol 27-hydroxylase gene. serum cholestanol concentrations were decreased with the HMG-CoA reductase inhibitor simvastatin alone and greater reductions were achieved after the addition of the bile acid chenodeoxycholic acid; suggesting a synergistic effect of this combination. Despite serum cholestanol concentrations remaining within the low-normal range, there has been no significant improvement in mental and physical abilities or in EEG abnormalities with 5 years of treatment. metabolism of radiolabeled 7-ketocholesterol to aqueous soluble products was absent in CTX-derived macrophages. Consistent with this finding, plasma 7 alpha-hydroxycholesterol, 7 beta-hydroxycholesterol, and 7-ketocholesterol concentrations were increased in the CTX subject compared with controls. ( info) |
8/41. Two cases of surgically treated hand tendon xanthomas. Two cases of sugically treated hand tendon xanthomas are presented. On surgical exploration, these xanthomas were found to be intertwined within the extensor mechanism. Total excision was not possible because it risked loss of integrity of the extensor mechanism. Both patients regained full range of motion and experienced no progressive tumor growth at a minimum of 1-year follow-up. ( info) |
| Cerebrotendinous xanthomatosis (CTX) is exceptionally rare in the Chinese population. We reported a 31-year-old Chinese male in hong kong, who has the characteristic features of cerebrotendinous xanthomatosis including the multiple xanthomas of tendons, mental retardation, bilateral cataracts, cerebellar ataxia and spasticity of the left arm, high concentrations of plasma phytosterols and abnormal MR of brain. On screening the family, two other siblings of 27 and 29 respectively, have tendon xanthomas and high plasma phytosterols. An extensive search of the international medical literature, including the medline, has revealed only one other case report of cerebrotendinous xanthomatosis in taiwan. CTX is a potentially treatable disease. It is hoped by alertness, early diagnosis and treatment can be made, and hence prevent further progression of the disease. ( info) |
| Cerebrotendinous xanthomatosis is a rare autosomal recessive lipid-storage disease caused by mutations in the sterol 27-hydroxylase gene. The accumulation of cholestanol in various tissues characterizes this disease. Diagnosis is based on determination of urinary bile alcohols. Therapy with chenodeoxycholic acid may arrest the progression of the disease. A 55-year-old woman presented with a slowly progressive paraparesia and two firm subcutaneous tumors over the knees. Her medical history revealed difficulty in standing and walking since infancy, bilateral juvenile cataracts, and mental retardation. Histopathologic examination of one subcutaneous tumor was consistent with tendinous xanthoma. Substantial elevation of urinary bile alcohols confirmed the diagnosis. Treatment with oral chenodeoxycholic acid was started, with only mild improvement of spasticity. Recognition of tendon xanthomas in a young patient with neurologic symptoms or cataracts (or both) is crucial to start early treatment and to avoid irreversible neurologic sequelae. ( info) |