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

Pathophysiology and Treatment of Lipid Abnormalities in Cerebrotendinous Xanthomatosis: An Integrative Review

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive disorder caused by pathogenic variants in CYP27A1, leading to a deficiency in sterol 27-hydroxylase. This defect results in the accumulation of cholestanol and bile alcohols in various tissues, including the brain, tendons and peripheral nerves. We conducted this review to evaluate lipid profile abnormalities in patients with CTX. A search was conducted in PubMed, Embase and the Virtual Health Library in January 2023 to evaluate studies reporting the lipid profiles of CTX patients, including the levels of cholestanol, cholesterol and other lipids. Elevated levels of cholestanol were consistently observed. Most patients presented normal or low serum cholesterol levels. A decrease in chenodeoxycholic acid (CDCA) leads to increased synthesis of cholesterol metabolites, such as bile alcohols 23S-pentol and 25-tetrol 3-glucuronide, which may serve as surrogate follow-up markers in patients with CTX. Lipid abnormalities in CTX have clinical implications. Cholestanol deposition in tissues contributes to clinical manifestations, including neurological symptoms and tendon xanthomas. Dyslipidemia and abnormal cholesterol metabolism may also contribute to the increased risk of atherosclerosis and cardiovascular complications observed in some CTX patients.

Ocular manifestations of liver disease in children: Clinical aspects and implications

Liver and eyes are interlinked to each other in various medical conditions. There are certain ocular findings which directly indicate specific liver disorders. Thus, it becomes critical to identify disorders of liver and eyes early in the course of illness, so that prompt management may be initiated before the commencement of complications. It is highly advantageous in metabolic liver disorders as it offers prognostic value and spares the patient of unnecessary invasive and detailed work up. However, due to its silent and heterogeneous presentation, it is often unrecognized and ignored. Eye abnormalities could be due to, either direct toxic effects of abnormal metabolites, excess of normal metabolites, or by deficient energy metabolism. A number of inherited liver conditions have associated ocular lesions such as Kayser-Fleischer rings in Wilson's disease, posterior embryotoxon or optic drusen in Alagille's syndrome, and cherry-red spot in Niemann-Pick's type A. A thorough eye examination is important in distinguishing between several different forms of familial intrahepatic cholestasis which are associated with anomalies of the heart, bones, or kidneys. Early diagnosis is important, as in most cases, dietary restriction and early therapy prevents the onset of disability. The aim of this review is to sensitize and make pediatricians, hepatologists and ophthalmologists aware of specific ocular findings, suggestive of certain hepatobiliary disorders, thus helping in early referral. The pediatric and adult literature was thoroughly reviewed to organize the present review.

Cerebrotendinous xanthomatosis-associated diarrhea and response to chenodeoxycholic acid treatment

BACKGROUND

In patients with cerebrotendinous xanthomatosis (CTX), chronic diarrhea is one of the earliest and main symptoms of the disease. In the current study, we evaluated the characteristics of the diarrhea and its response to chenodeoxycholic acid (CDCA) therapy in a cohort of Dutch CTX patients.

METHODS

We performed a retrospective review of medical records for 33 genetically confirmed CTX patients, and abstracted the characteristics of the diarrhea and the response to CDCA therapy (15 mg/kg/day up to 750 mg/day). The Bristol Stool Scale (BSS) was used for qualitative characterization of the stool.

RESULTS

Twenty-five patients had diarrhea documented at baseline (76%). Of these patients, 10 had diarrhea rated as 6 (fluffy pieces with ragged edges, a mushy stool), and 6 had diarrhea rated as 7 (watery, no solid pieces, entirely liquid) using the BSS. In 10 patients for whom data were recorded, the median stool frequency at baseline was 3 per day (range 2-6 per day). The response rate with CDCA for diarrhea resolution was 100% based on at least one post-baseline visit without diarrhea and 95% as assessed at the first post-baseline visit. In 68% of cases resolution was complete and sustained as no episodes of diarrhea were documented for follow-up periods as long as 25 years.

CONCLUSIONS

Chronic diarrhea persisting for years without spontaneous remission is a common feature of CTX at diagnosis. Chenodeoxycholic acid is an effective treatment for symptomatic relief of diarrhea in patients with CTX.

Adulthood leukodystrophies

The leukodystrophies are a group of inherited white matter disorders with a heterogeneous genetic background, considerable phenotypic variability and disease onset at all ages. This Review focuses on leukodystrophies with major prevalence or primary onset in adulthood. We summarize 20 leukodystrophies with adult presentations, providing information on the underlying genetic mutations and on biochemical assays that aid diagnosis, where available. Definitions, clinical characteristics, age of onset, MRI findings and treatment options are all described, providing a comprehensive overview of the current knowledge of the various adulthood leukodystrophies. We highlight the distinction between adult-onset leukodystrophies and other inherited disorders with white matter involvement, and we propose a diagnostic pathway for timely recognition of adulthood leukodystrophies in a routine clinical setting. In addition, we provide detailed clinical information on selected adult-onset leukodystrophies, including X-linked adrenoleukodystrophy, metachromatic leukodystrophy, cerebrotendinous xanthomatosis, hereditary diffuse leukoencephalopathy with axonal spheroids, autosomal dominant adult-onset demyelinating leukodystrophy, adult polyglucosan body disease, and leukoencephalopathy with vanishing white matter. Ultimately, this Review aims to provide helpful suggestions to identify treatable adulthood leukodystrophies at an early stage in the disease course.

Cerebrotendinous xanthomatosis: a rare disorder with a rare presentation

A young man was brought for mental retardation, frequent non-bloody diarrhoea and swellings at ankles and elbow. He became bed-ridden due to cataract, mental retardation and pain in the back and lower limb. There were repeated pathological fractures and vitamin D deficiency without renal dysfunction. There were low low-density lipoprotein and triglyceride levels. MRI of the brain revealed hypointense lesions in cerebellar white matter, heterogenous hyperintensity in dentate nucleus and adjacent white matter, right basal ganglia and in the periventricular region with diffuse cerebral atrophy. T1-weighted MRI (ankle region) revealed bilaterally thickened and irregular achilles tendons with hyperintense masses surrounded by patchy hypointensities. A similar xanthomatous lesion (cholestanol deposits) was also present in the sacral region. Vitamin D and calcium supplementation and chenodeoxycholic acid therapy improved pain at lower limbs and body weight. Cerebrotendinous xanthomatosis is a rare autosomal-recessive familial mutation of the sterol 27 hydroxylase causing lipid metabolic disease.

Cerebrotendinous xanthomatosis: a rare disorder with a rare presentation

A young man was brought for mental retardation, frequent non-bloody diarrhoea and swellings at ankles and elbow. He became bed-ridden due to cataract, mental retardation and pain in the back and lower limb. There were repeated pathological fractures and vitamin D deficiency without renal dysfunction. There were low low-density lipoprotein and triglyceride levels. MRI of the brain revealed hypointense lesions in cerebellar white matter, heterogenous hyperintensity in dentate nucleus and adjacent white matter, right basal ganglia and in the periventricular region with diffuse cerebral atrophy. T1-weighted MRI (ankle region) revealed bilaterally thickened and irregular achilles tendons with hyperintense masses surrounded by patchy hypointensities. A similar xanthomatous lesion (cholestanol deposits) was also present in the sacral region. Vitamin D and calcium supplementation and chenodeoxycholic acid therapy improved pain at lower limbs and body weight. Cerebrotendinous xanthomatosis is a rare autosomal-recessive familial mutation of the sterol 27 hydroxylase causing lipid metabolic disease.

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.

Inherited metabolic disorders involving the eye: a clinico-biochemical perspective

The diagnosis of inborn errors of metabolism is challenging for most physicians. Improvements in medical technology and greater knowledge of the human genome are resulting in significant changes in the diagnosis, classification, and treatment of inherited metabolic disorders (IMDs). Many known inborn errors of metabolism will be recognised earlier or treated differently because of these changes. It is important that physicians recognise the clinical signs of IMDs and know when to propose advanced laboratory testing or referral to a higher centre for better patient management. Ocular manifestations occur in various metabolic disorders. Although there is an extensive understanding of many inborn errors of metabolism at the biochemical, molecular, and metabolic levels, little is known about their pathogenesis. In particular, how systemic metabolic disease contributes to ocular defects remains to be elucidated in IMDs. The occurrence of eye abnormalities could be due to direct toxic mechanisms of abnormal metabolic products or accumulation of normal metabolites by errors of synthetic pathways or by deficient energy metabolism. A detailed ophthalmological assessment is essential. Definitive diagnosis and management of patients with IMDs is ideally carried out by a combination of specialists, including an ophthalmologist, paediatrician, biochemist, and medical geneticist. Recent advances in the diagnosis and treatment of IMDs have substantially improved the prognosis for many of these conditions.

Cerebrotendinous xanthomatosis: a critical update

Cerebrotendinous xanthomatosis (CTX) also known as van Bogaert–Scherer–Epstein syndrome, Thiebaut’s syndrome and cerebrotendinous cholesterosis, is an autosomal-recessive lipid-storage disease characterized by the triad of juvenile cataracts, tendon xanthomas and progressive neurodegeneration. Excess cholesterol and cholestanol are deposited in multiple organs, including the cerebrum, cerebellum, lens and tendons. Approximately 300 cases are reported worldwide, but it is suspected that the incidence of CTX is underestimated. The disease is attributed to approximately 50 mutations in the CYP27A1 gene coding for the enzyme sterol 27-hydoxylase, which is responsible for initial oxidation of the side chain of the cholesterol molecule in bile acid biosynthesis. CTX has varied clinical presentations, but no genotype–phenotype relationship has been documented. In some intrafamilial cases, clinical presentations may vary considerably. MRI for CTX is sensitive for diagnosis and classically demonstrates cerebral and cerebellar atrophy and xanthomatous lesions preferentially affecting the dentate nuclei. Patients have high serum levels of cholestanol with normal total cholesterol and increased urinary excretion of bile acids. Treatment of patients with chenodeoxycholic acid, particularly when used along with HMG-CoA reductase inhibitors (statins) or low-density lipoprotein apheresis, can normalize cholestanol levels as well as prevent further degeneration. Therefore, the need for early diagnosis is well documented in the literature, as it prevents the significant morbidity and mortality associated with this disease.

High-throughput urine screening for Smith-Lemli-Opitz syndrome and cerebrotendinous xanthomatosis using negative electrospray tandem mass spectrometry

BACKGROUND

Smith-Lemli-Opitz syndrome (SLOS) and cerebrotendinous xanthomatosis (CTX) are disorders affecting cholesterol metabolism. Currently, diagnosis relies on clinical recognition and specific and complex biochemical testing.

METHODS

A rapid, high-throughput urine test, suitable for mass screening for these two disorders, was developed using flow injection negative electrospray tandem mass spectrometry with multiple reaction monitoring. Cholestane-pentol glucuronide, a known marker for CTX, was measured and a steroid sulfate with a proposed keto-pregnadien-diol structure was identified and measured for SLOS. Measurement of the two markers was readily incorporated into an existing tandem mass spectrometry method for diagnosing inborn errors of amino and organic acid metabolism.

RESULTS

Levels in affected patients were well separated from 1738 controls, ranging from 6.7 to 100 times the 99.7th percentile of controls in SLOS patients (n=3) and 7.3 to 24 times the 99.7th percentile of controls in CTX patients (n=4).

CONCLUSIONS

The addition of testing for SLOS and CTX to a routine tandem mass spectrometry urine screening program simplifies the diagnosis of these two disorders and further extends the range of inborn errors of metabolism detected by this technique.

A new method for determination of serum cholestanol by high-performance liquid chromatography with ultraviolet detection

We developed a method for the determination of serum 5alpha-cholestan-3beta-ol (cholestanol). The sterols were derivatized to the 4'-bromobenzenesulfonyl esters and heated in isopropanol. The cholesterol-4'-bromobenzenesulfonate was solvolyzed to cholesteryl isopropyl ether, but the derivatized cholestanol did not change and could be measured in a high-performance liquid chromatographic system equipped with a UV detector at 235 nm. On the other hand, the resulting cholesteryl isopropyl ether, having different absorbance and chromatographic mobility was not detected. This method was used for measuring cholestanol levels in patients with cerebrotendinous xanthomatosis (CTX), liver cirrhosis and serum from healthy control subjects. Reproducibility, linearity and recovery tests were done on 0.3 ml of serum samples containing >2 microg/ml cholestanol, using stigmastanol as an internal standard (I.S.). Determining cholestenol by this method can be used for diagnosis and follow-up of patients with CTX and various liver diseases.

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.

Cerebrotendinous xanthomatosis: pathophysiological study on bone metabolism

A condition of osteopenia in some cerebrotendinous xanthomatosis (CTX) patients led us to investigate bone metabolism in 8 patients belonging to 5 families. Serum calcium, phosphate and vitamin D metabolites were in the normal range; a reduction in total body density and impairment of intestinal radiocalcium absorption were found in the majority of our patients.

Cyclosporine, low-density lipoprotein, and cholesterol

Lipoproteins are known to be able to transport a variety of drugs. This report suggests that low-density lipoprotein not only functions as an important carrier of cyclosporine in plasma but also facilitates transport of cyclosporine across the cell membrane by means of the low-density lipoprotein receptor. Such a mechanism would explain (1) the similar tissue distribution of cyclosporine and the low-density lipoprotein receptor, (2) the increase in immunosuppression and toxicity with low total serum cholesterol levels, and (3) the relative absence of immunosuppression and toxicity with high levels of cyclosporine in the blood in patients with hypertriglyceridemia. In addition to receptor-mediated uptake, a disturbance of the blood-brain barrier is suggested as an explanation of the high frequency of cyclosporine-induced central nervous system toxicity after liver transplantation. Cyclosporine-induced inhibition of the mitochondrial steroid 26-hydroxylase, an enzyme involved in the formation of bile acids from cholesterol and deficient in patients with cerebrotendinous xanthomatosis, may cause or contribute to the observed central nervous system toxicity. It also may explain the similar clinical features of cyclosporine-induced central nervous system toxicity and cerebrotendinous xanthomatosis.