Cerebrotendinous xanthomatosis (CTX): a clinical survey of the patient population in The Netherlands

Disorders with prominent posterior fossa involvement

Inherited white matter disorders include a wide range of disorders of various origins with distinct genetic, pathophysiologic, and metabolic backgrounds. Although most of these diseases have nonspecific clinical and radiologic features, some display distinct clinical and/or imaging (magnetic resonance imaging, MRI) characteristics that might suggest the causative gene. Recent advances in genetic testing allow assessing gene panels that include several hundred genes; however, an MRI-based diagnostic approach is important to narrow the choice of candidate genes, particularly in countries where these techniques are not available. Indeed, white matter disorders with prominent posterior fossa involvement present specific MRI (and clinical) phenotypes that can directly orient the diagnosis. This chapter describes the main genetic disorders with posterior fossa involvement and discusses diagnostic strategies.

Cerebrotendinous Xanthomatosis: Molecular Pathogenesis, Clinical Spectrum, Diagnosis, and Disease-Modifying Treatments

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive lipid storage disorder caused by mutations in the CYP27A1 gene, which encodes the mitochondrial enzyme sterol 27-hydroxylase. Decreased sterol 27-hydroxylase activity results in impaired bile acid synthesis, leading to reduced production of bile acids, especially chenodeoxycholic acid (CDCA), as well as elevated serum cholestanol and urine bile alcohols. The accumulation of cholestanol and cholesterol mainly in the brain, lenses, and tendons results in the characteristic clinical manifestations of CTX. Clinical presentation is characterized by systemic symptoms including neonatal jaundice or cholestasis, refractory diarrhea, juvenile cataracts, tendon xanthomas, osteoporosis, coronary heart disease, and a broad range of neuropsychiatric manifestations. The combinations of symptoms vary from patient to patient and the presenting symptoms, especially in the early disease phase, may be nonspecific, which leads to a substantial diagnostic delay or underdiagnosis. Replacement of CDCA has been approved as a first-line treatment for CTX, and can lead to biochemical and clinical improvements. However, the effect of CDCA treatment is limited once significant neuropsychiatric manifestations are established. The age at diagnosis and initiation of CDCA treatment correlate with the prognosis of patients with CTX. Therefore, early diagnosis and subsequent treatment initiation are essential.

Cholic acid as a treatment for cerebrotendinous xanthomatosis in adults

Cerebrotendineous xanthomatosis (CTX) is an autosomal recessive disorder of bile acids synthesis. Patients may present with a variety of clinical manifestations: bilateral cataract and chronic diarrhea during childhood, then occurrence of neurological debilitating symptoms in adulthood (cognitive decline, motor disorders). Plasma cholestanol is used as a diagnostic marker of CTX, and to monitor the response to the treatment. Current treatment for CTX is chenodeoxycholic acid (CDCA), which was reported to improve and/or stabilize clinical status and decrease levels of plasma cholestanol. Rare published reports have also suggested a potential efficacy of cholic acid (CA) in patients with CTX. In this retrospective Franco-Belgian multicentric study, we collected data from 12 patients treated with CA, evaluating their clinical status, cholestanol levels and adverse effects during the treatment period. The population was divided in two subgroups: treatment-naive (who never had CDCA prior to CA) and non-treatment-naive patients (who had CDCA prior to CA introduction). We found that treatment with CA significantly and strongly reduced cholestanol levels in all patients. Additionally, 10 out of 12 patients clinically improved or stabilized with CA treatment. Worsening was noted in one treatment-naïve patient and one non-treatment-naïve patient, but both patients experienced similar outcomes with CDCA treatment as well. No adverse effects were reported from patients with CA treatment, whereas elevated transaminases were observed in some patients while they were treated with CDCA. In conclusion, these findings suggest that CA may be a suitable alternative treatment for CTX, especially in patients with side effects related to CDCA.

Cholic acid as a treatment for cerebrotendinous xanthomatosis in adults

Cerebrotendineous xanthomatosis (CTX) is an autosomal recessive disorder of bile acids synthesis. Patients may present with a variety of clinical manifestations: bilateral cataract and chronic diarrhea during childhood, then occurrence of neurological debilitating symptoms in adulthood (cognitive decline, motor disorders). Plasma cholestanol is used as a diagnostic marker of CTX, and to monitor the response to the treatment. Current treatment for CTX is chenodeoxycholic acid (CDCA), which was reported to improve and/or stabilize clinical status and decrease levels of plasma cholestanol. Rare published reports have also suggested a potential efficacy of cholic acid (CA) in patients with CTX. In this retrospective Franco-Belgian multicentric study, we collected data from 12 patients treated with CA, evaluating their clinical status, cholestanol levels and adverse effects during the treatment period. The population was divided in two subgroups: treatment-naive (who never had CDCA prior to CA) and non-treatment-naive patients (who had CDCA prior to CA introduction). We found that treatment with CA significantly and strongly reduced cholestanol levels in all patients. Additionally, 10 out of 12 patients clinically improved or stabilized with CA treatment. Worsening was noted in one treatment-naïve patient and one non-treatment-naïve patient, but both patients experienced similar outcomes with CDCA treatment as well. No adverse effects were reported from patients with CA treatment, whereas elevated transaminases were observed in some patients while they were treated with CDCA. In conclusion, these findings suggest that CA may be a suitable alternative treatment for CTX, especially in patients with side effects related to CDCA.

Long-term treatment effect in cerebrotendinous xanthomatosis depends on age at treatment start

Objective

To evaluate the effect of chenodeoxycholic acid treatment on disease progression in cerebrotendinous xanthomatosis (CTX).

Methods

In this retrospective cohort study, we report the clinical long-term follow-up characteristics of 56 Dutch patients with CTX. Age at diagnosis was correlated with clinical characteristics and with the course of modified Rankin Scale (mRS) and Expanded Disability Status Scale (EDSS) scores at follow-up.

Results

Median follow-up time was 8 years (6 months–31.5 years). Patients diagnosed and treated before the age of 24 years had a significantly better outcome at follow-up. When considering only patients with a good treatment adherence (n = 43), neurologic symptoms, if present, disappeared in all patients who were diagnosed before the age of 24 and treated since. Furthermore, treatment prevented the development of new neurologic symptoms during follow-up. In contrast, 61% of the patients diagnosed and treated after the age of 24 showed deterioration of the neurologic symptoms, with parkinsonism as a treatment-resistant feature. There was an improvement or stabilization in favor of patients diagnosed and treated before the age of 24 compared to those treated after the age of 24: 100% vs 58% for mRS scores and 100% vs 50% for EDSS scores, respectively.

Conclusions

Treatment start at an early age can reverse and even prevent the development of neurologic symptoms in CTX. This study emphasizes the importance of early diagnosis in CTX and provides a rationale to include CTX in newborn screening programs.

Epidemiology, diagnosis, and treatment of cerebrotendinous xanthomatosis (CTX)

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disorder of bile acid synthesis caused by mutations in the cytochrome P450 CYP27A1 gene that result in production of a defective sterol 27-hydroxylase enzyme. CTX is associated with abnormally high levels of cholestanol in the blood and accumulation of cholestanol and cholesterol in the brain, tendon xanthomas, and bile. Hallmark clinical manifestations of CTX include chronic diarrhea, bilateral cataracts, tendon xanthomas, and neurologic dysfunction. Although CTX is a rare disorder, it is thought to be underdiagnosed, as presenting signs and symptoms may be nonspecific with significant overlap with other more common conditions. There is marked variability in signs and symptoms, severity, and age of onset between patients. The disease course is progressive and potentially debilitating or fatal, particularly with respect to neurologic presentations that can include intellectual disability, autism, behavioral and psychiatric problems, and dementia, among others. Treatment with chenodeoxycholic acid (CDCA; chenodiol) is the current standard of care. CDCA can help restore normal sterol, bile acid, bile alcohol, and cholestanol levels. CDCA also appears to be generally effective in preventing adverse clinical manifestations of the disease from occurring or progressing if administered early enough. Improved screening and awareness of the condition may help facilitate early diagnosis and treatment.

Psychiatric manifestations in cerebrotendinous xanthomatosis

Cerebrotendinous xanthomatosis (CTX) is a rare and severe, but treatable, inborn disorder of bile acid biosynthesis and sterol storage with autosomal recessive inheritance and variable clinical presentation. CTX treatment consists of chenodeoxycholic acid and must be started as early as possible to prevent permanent disability. Psychiatric manifestations are rare and non-specific, and often lead to significant diagnostic and treatment delay. Therefore, better recognition of the gamut of psychiatric manifestations in CTX can diminish the risk of misdiagnosis and irreversible neurological deterioration. We hereby describe the psychiatric features in CTX. A complete review of all published cases of CTX in the medical literature was undertaken and the case reports with psychiatric presentation were collected and analyzed. We also describe the psychiatric features in relation to the neurological semeiology in six patients with CTX diagnosed at the La Salpêtrière Hospital. We conclude that psychiatric manifestations in CTX follow a bimodal/bitemporal pattern, appearing early in the disease course in the form of a behavioral/personality disorder associated with learning difficulties or mental retardation, or manifesting in advanced disease in the setting of dementia as rich neuropsychiatric syndromes, such as frontal, orbitofrontal or frontotemporal syndromes of cortico-subcortical dementia encompassing behavioral/personality disturbance, affective/mood disorders or psychotic disorders. Behavioral/personality disturbance in childhood or adolescence, especially when accompanied by learning difficulties, should therefore lead to further investigation to exclude CTX, as early diagnosis and treatment is critical for prognosis.

Cerebrotendinous xanthomatosis: a rare cause of spinocerebellar syndrome

A 34-year-old patient demonstrating pyramidal and cerebellar signs, accompanied by epilepsy, peripheral neuropathy, mental retardation and bilateral cataract was diagnosed with cerebrotendinous xanthomatosis based on the clinical picture, magnetic resonance imaging of the brain and serum sterol analysis. Tendon xanthomas were not observed in this case. After establishing the diagnosis, treatment with chenodeoxycholic acid and statin was introduced. During the next two years of the follow-up, serum cholestanol and 7α-hydroxycholesterol levels decreased in response to the therapy, but this was not reflected in the patient's neurological condition, which was slowly progressing. Treatment effectiveness in cerebrotendinous xanthomatosis is variable, notably better in patients who had started therapy before the injury to the nervous system took place. The present case report points to cerebrotendinous xanthomatosis as a rare cause of spinocerebellar syndrome, which might be treatable if diagnosed in early life.

Prevalence of Epilepsy among Cataract Patients

PURPOSE

To evaluate the prevalence of epilepsy among patients undergoing cataract surgery.

DESIGN

A retrospective observational case control study.

METHODS

We calculated the prevalence of epilepsy among all the patients older than 50 years who underwent cataract surgery (years 2000-2007, n = 12,984) in a district of the largest health maintenance organization in Israel (the Central District of Clalit Health Services) and among 25,968 age and gender matched controls. The database was screened for epilepsy by integrating the clinical and ancillary work-up as well as the drug regimen. The use of anti-epileptic drugs (AEDs) was evaluated among the cataract patients and the controls. The main outcome measure was the prevalence of epilepsy and antiepileptic medical treatment among patients undergoing cataract surgery versus controls.

RESULTS

No difference was found in demographics among the groups including age, gender, marriage status, socioeconomic class and living place between the study and control groups (except for patients origin). Epilepsy was found to be significantly more prevalent in patients undergoing cataract surgery. The odds ratio (OR) was 1.3 (95% confidence interval (CI): 1.1-1.6): 1.4 in men (95% CI: 1.1-1.9) and 1.2 in women (95% CI: 1.0-1.6). AEDs, particularly clonazepam (OR = 1.5, 95% CI: 1.1-2.1) and carbamazepine (OR = 1.4, 95% CI: 1.05-1.8), were also used more by cataract patients. Multivariate logistic regression analysis revealed a significant association between cataract surgery and epilepsy (OR 1.26, p < 0.001) as well as diabetes (OR 1.38, p < 0.001), arterial hypertension (OR 1.26, p < 0.001), smoking (OR 1.22, p < 0.001), hyperlipidemia (OR 1.12, p < 0.001), and Ashkenazi origin (OR 0.85, p < 0.001).

CONCLUSIONS

Epilepsy is associated with the presence of cataract. Various hypotheses may explain this finding, including a cataractogenic role of AEDs.

Epilepsy in inherited metabolic disorders

INTRODUCTION

The study of neurometabolic diseases is still in a prolonged preliminary stage. The catalogue of these diseases continues to grow; some known clinical syndromes have been subdivided into a number of variants once the genes that cause them have been identified, and at the same time new metabolic disorders have been discovered that aggravate or contribute to forms of epilepsy not previously classified as cerebral metabolic disorders.

RESULTS

This review presents the basic principles underlying the recognition and treatment of epilepsy caused by neurometabolic diseases. These disorders are divided (purely for the sake of convenience) into epilepsy presenting in newborn infants, children, and adolescents and adults, recognizing that there is a significant degree of overlap between these chronological stages. Current analytical methods and therapeutic approaches are summarized both from a general point of view and within the context of each clinical syndrome, acknowledging that each patient presents specific peculiarities and that, in general, antiepileptic drugs provide few benefits compared with more specific types of therapy (eg, special diets or vitamins) when indicated. We also include therapeutic recommendations and a general approach to fulminant epilepsies of neurometabolic origin, emphasizing the importance of identifying all of the proband's relatives who may be potential carriers of a genetic disorder during the diagnostic and genetic counselling process. Particular emphasis is placed on disorders for which there is curative treatment and on the importance of follow-up by expert professionals.

CONCLUSION

It is expected that in a few years' time it will be possible to know the metabolomic profile of these diseases (possibly by non-invasive methods), thus facilitating accurate diagnosis and making it possible to establish the response to treatment and to identify all individuals who are carriers or remain minimally symptomatic in terms of their risk of manifesting or transmitting epilepsy.

Cerebrotendinous xanthomatosis: clinical manifestations, diagnostic criteria, pathogenesis, and therapy

In this report, we review the clinical, biochemical, pathophysiologic, and therapeutic aspects of cerebrotendinous xanthomatosis. We stress the importance of early diagnosis and treatment. In addition, we describe our experience in treating patients with chenodeoxycholic acid, an essential drug for this disorder that is no longer available.

Cerebrotendinous xanthomatosis: 11-year treatment with chenodeoxycholic acid in five patients. An electrophysiological study

We report the electrophysiological follow-up of five cerebrotendinous xanthomatosis patients treated for 11 years with chenodeoxycholic acid (CDCA). Nerve conduction velocity (NCV) was reduced in three cases. P100 latency of visual evoked potentials was delayed in four cases, interpeaks I-III and I-V of brainstem auditory evoked potentials (BAEPs) was increased in two and interpeak N13-20 of upper limb somatosensory evoked potentials (SEPs) was slowed in one. After 4 months of therapy with CDCA, NCV was normal and did not show any significant change during the 11 years of observation. Central motor conduction time of motor evoked potentials (MEPs) and N24-P40 interpeak latency of lower limb SEPs were increased in five and four cases, respectively, in spite of 2/3-year treatment with CDCA. Improvement of evoked potentials, especially of MEPs and SEPs, was slower and continued over the whole 11-year period. The size of xanthomas slightly decreased in some patients during treatment and the clinical manifestations stabilized, avoiding progressive worsening, but there was no significant improvement in neurological deficit. Two sisters of patients who never took CDCA showed progressive worsening of clinical manifestations, upper limb SEPs and BAEPs.

Cerebrotendinous xanthomatosis: the spectrum of imaging findings and the correlation with neuropathologic findings

PURPOSE

To describe imaging findings and their neuropathologic correlate in patients with cerebrotendinous xanthomatosis (CTX).

MATERIALS AND METHODS

Computed tomographic (CT) and magnetic resonance (MR) images in 24 patients with symptoms (mean age at time of imaging, 37 years; mean disease duration, 18 years) were reviewed for site and frequency of brain, spinal cord, and Achilles tendon involvement. Two patients died, and imaging findings were compared with postmortem neuropathologic findings.

RESULTS

Apart from nonspecific supratentorial atrophy and deep white matter changes, more typical hyperintense lesions were seen on T2-weighted images in the dentate nucleus (in 79% of patients), globus pallidus, substantia nigra, and inferior olive and extended into adjacent white matter as disease progressed. In these locations, lipid crystal clefts and perivascular macrophages, neuronal loss, demyelination, fibrosis, and reactive astrocytosis were found at microscopic examination. Hypointensity was sometimes found on T2-weighted images in the dentate nucleus and was related to deposition of hemosiderin and calcifications. CT depicted fewer lesions; all had low attenuation, except for the calcifications. Spinal cord MR imaging revealed increased signal intensity in the lateral and dorsal columns on T2-weighted images. Achilles tendon xanthomas displayed intermediate signal intensity on T1- and T2-weighted images.

CONCLUSION

The typical pattern of MR imaging findings reflects the classic histopathologic findings and should prompt the diagnosis of CTX.

Cerebrotendinous xanthomatosis. Controversies about nerve and muscle: observations in ten patients

Neuromuscular characteristics were documented in ten patients with biochemically and genetically confirmed cerebrotendinous xanthomatosis. An array of genotypes was found in these patients. Only one patient complained of muscle weakness, while clinical signs of peripheral neuropathy were present in six patients. Electromyogram showed predominantly axonal neuropathy in seven patients. Neurogenic changes were seen in muscle biopsies of nine patients. Sural nerve biopsies of three patients showed features of axonal neuropathy. In addition, in one patient, extensive onion bulb formation was seen, which is indicative of a primarily demyelinating process. Five patients had normal mitochondrial respiratory chain enzyme activity. It is concluded that myopathy is not a feature of cerebrotendinous xanthomatosis and that the most prominent neuromuscular abnormality is sensorimotor axonal polyneuropathy.

Clinical and molecular genetic characteristics of patients with cerebrotendinous xanthomatosis

Cerebrotendinous xanthomatosis (CTX) is a lipid storage disease caused by a deficiency of the mitochondrial enzyme 27-sterol hydroxylase (CYP 27), due to mutations in its gene. In this study we report on mutations in 58 patients with CTX out of 32 unrelated families. Eight of these were novel mutations, two of which were found together with two already known pathogenic mutations. Twelve mutations found in this patient group have been described in the literature. In the patients from 31 families, mutations were found in both alleles. In the literature, 28 mutations in 67 patients with CTX out of 44 families have been described. Pooling our patient group and the patients from the literature together, 37 different mutations in 125 patients out of 74 families were obtained. Identical mutations have been found in families from different ethnic backgrounds. In 41% of all the patients, CYP 27 gene mutations are found in the region of exons 6-8. This region encodes for adrenodoxin and haem binding sites of the protein. Of these 125 patients, a genotype-phenotype analysis was done for 79 homozygous patients harbouring 23 different mutations, out of 45 families. The patients with compound heterozygous mutations were left out of the genotype-phenotype analysis. The genotype-phenotype analysis did not reveal any correlation.

Chronic diarrhoea as a dominating symptom in two children with cerebrotendinous xanthomatosis

The objective of this study was to describe diarrhoea as a dominating symptom of cerebrotendinous xanthomatosis (CTX), a lipid storage disease, and investigate its cause. Two children with chronic diarrhoea as the dominating symptom of CTX are presented. Before and after therapy with orally administered chenodeoxycholic acid (15 mg kg-1 24 h, in three divided doses) bile alcohol excretion in urine, serum cholestanol level, serum bile acid patterns and faecal bile acids were measured. All routine gastro-intestinal investigations before therapy were normal. Diarrhoea ceased immediately after starting treatment with chenodeoxycholic acid. Abnormal bile alcohol excretion in urine decreased rapidly during the first days and elevated serum cholestanol level normalized in 2 years. We postulate the presence of bile alcohols in the lumen of the gut as most likely cause for diarrhoea in CTX, since the rapid decrease of bile alcohol excretion is associated with prompt cessation of diarrhoea after starting treatment with chenodeoxycholic acid.

Cerebrotendinous xanthomatosis without tendon xanthomas mimicking Marinesco-Sjoegren syndrome: a case report

A 39 year old patient with cerebellar signs, juvenile cataracts, and dull normal intelligence had cerebrotendinous xanthomatosis without tendon xanthomas, diagnosed previously as Marinesco-Sjoegren syndrome. Cerebrotendinous xanthomatosis was proved by a greatly increased excretion of bile alcohols in the patient's urine. Cerebrotendinous xanthomatosis is a sterol storage disorder due to an autosomal recessive inherited defect of sterol 27-hydroxylase characterised by high cholestanol concentration in multiple tissues. If tendon xanthomas are not present, a diagnosis of cerebrotendinous xanthomatosis will often not be made, unless biochemical tests are performed. The clinical features of cerebrotendinous xanthomas strongly resembles Marinesco-Sjoegren syndrome. Marinesco-Sjoegren syndrome is a autosomal recessive disorder characterised by the triad cerebellar ataxia, congenital cataract, and mental retardation. Although a late onset after the first decade of life favours cerebrotendinous xanthomatosis as the underlying disease, a definite distinction between cerebrotendinous xanthomatosis without tendon xanthomas and Marinesco-Sjoegren syndrome based on clinical presentation may be difficult. It is considered that some patients with Marinesco-Sjoegren syndrome reported in the medical literature had cerebrotendinous xanthomatosis without tendon xanthomas. This is of crucial clinical relevance, because, by contrast with Marinesco-Sjoegren syndrome, treatment for cerebrotendinous xanthomatosis is already available.

The neuropathology of cerebrotendinous xanthomatosis revisited: a case report and review of the literature

Cerebrotendinous xanthomatosis (CTX), a rare autosomal-recessive lipid storage disease, has been well characterized clinically and biochemically, and recently also from the molecular biological aspect. However, only a very few publications deal with its neuropathology, and views on its pathogenesis vary. Based on a recently examined case, we propose that central-peripheral distal axonopathy is the major pathogenetic mechanism of nervous system injury in CTX. The latter is characterized by white matter pathology, typically in form of long tract involvement with the more distal parts of the tract more severely affected. Most severely affected are the cerebellar white matter, the optic pathways and the long tracts of the brain stem and spinal cord, particularly the pyramidal tracts, although there is hardly a CNS region which does not display some form of pathology. Lesions are characterized by loss of myelinated fibers and accumulation of lipid products in form of foamy macrophages, clear oil-red-O-positive spaces and crystalline clefts, accompanied by gliosis, occasional axonal spheroids, and in the cerebellum--the most severely affected structure--also by multi-nucleated foreign body giant cells. Demyelination is not seen, and ultrastructurally myelin sheaths are normally structured. Signs of axonal degeneration are also present in the spinal roots. We hypothesize that the basic enzymatic defect in CTX leads to accumulation of metabolites in the brain which may be neurotoxic and may impair the metabolic apparatus of neurons with resultant axonopathy and subsequent nonspecific lipid deposition in the injured tracts.

Cerebrotendinous xanthomatosis: cranial CT and MRI studies in eight patients

We report the findings on cranial computed tomography (CT) and magnetic resonance imaging (MRI) and their correlation with the clinical manifestations, disease severity and biochemical abnormalities in eight patients with cerebrotendinous xanthomatosis. CT revealed cerebral atrophy in seven cases, cerebellar atrophy in four and focal low density lesions in the cerebral white matter in two. T2-weighted MRI showed high signal lesions in the cerebral white matter, focal in four cases and diffuse in one, and in the globus pallidus in three patients, two of whom also had lesions in the cerebellar white matter. While severely affected patients showed variable CT and MRI abnormalities, our cases did not show the dramatic findings expected from the neurological manifestations. Diffuse lesions in the cerebral and cerebellar white matter have been emphasized in previous reports, but in our study the focal lesions in the cerebral white matter were also present; the globus pallidus was frequently involved.

Cerebrotendinous xanthomatosis: clinical and biochemical evaluation of eight patients and review of the literature

We present the clinical and laboratory findings of 8 patients with cerebrotendinous xanthomatosis. The clinical features consisted of a combination of bilateral Achilles tendon xanthomas, cataracts, low intelligence, pyramidal signs, cerebellar signs, convulsions, peripheral neuropathy, foot deformity, cardiovascular disease or atherosclerosis, EEG abnormality, and increased CSF protein. Increased cholesterol was present in the serum, CSF and red cell membrane of all 8 patients. The bile of one patient with late age onset of the disease showed an attenuated production of bile acids and bile alcohols. Three of the 7 had obstruction and/or marked narrowing of the coronary arteries. Data on 136 patients reported throughout the world are reviewed.

Cerebrotendinous xanthomatosis: clinical and MRI study (a case report)

We report a patient with cerebrotendinous xanthomatosis (CTX) presenting with dementia, spastic tetraparesis and an unreported akinetic-rigid syndrome. Computed tomography (CT) showed only cerebellar abnormalities while magnetic resonance imaging (MRI) detected additional pallidal and mesencephalic focal alterations. MRI findings, but not CT, correlated with the clinical picture.

Cerebrotendinous xanthomatosis: a review of biochemical findings of the patient population in The Netherlands

This study gives a review of the results obtained from biochemical investigations of 20 patients in The Netherlands suffering from cerebrotendinous xanthomatosis, an inborn error of metabolism in bile acid synthesis. Diagnosis can best be established by determining the excretion of urinary bile alcohols, in particular 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha,23,25-pentol, in urine by means of capillary gas chromatography. Measurement of serum cholestanol levels or serum cholestanol/cholesterol ratios, commonly used for establishing cerebrotendinous xanthomatosis, are not reliable. The effectiveness of the different therapies, i.e. administration of bile acids, can be evaluated by monitoring the urinary excretion of bile alcohols. From such investigations it was concluded that cholic acid especially, but also chenodeoxycholic acid are the therapies of choice for the treatment of cerebrotendinous xanthomatosis. All patients, until now diagnosed in The Netherlands were not discovered before the third or fourth decade of life because the characteristic signs only then become manifest clearly. Unfortunately, because sterol storage is almost irreversible, therapy only results in minor improvements of the patient's condition. Therefore early detection of the presence of cerebrotendinous xanthomatosis is desirable so that treatment can start before extensive storage of sterols is a fact. We developed some laboratory assays with the purpose of early detection. One consists of the detection of cerebrotendinous xanthomatosis carriers by subjecting them to oral cholestyramine administration and monitoring the urinary excretion of the bile alcohol 5 beta-cholestane-3 alpha,7 alpha,12 alpha,23,25-pentol before and after treatment. Secondly, a relatively simple screening test for cerebrotendinous xanthomatosis was developed based on an enzymatic assay of 7 alpha-hydroxylated steroids in urine. After suitable modification this assay in principle allows the screening of large populations for the existence of cerebrotendinous xanthomatosis and thus to detect the disease at an earlier stage of life.