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

Glycodeoxycholic acid as alternative treatment in 3β-hydroxy-Δ5-C27-steroid-oxidoreductase: a case report

Background

3β-hydroxy-Δ5-C27-steroid-oxidoreductase (3β-HSD) deficiency is a bile acid synthesis disorder that leads to the absence of normal primary bile acids and the accumulation of abnormal bile acids. This results in cholestatic jaundice, fat-soluble vitamin deficiency, acholic or fatty stools and failure to thrive. Bile acid supplementation is used to treat 3β-HSD-deficiency and its symptoms.

Methods

This report details the case of a 28-year-old woman diagnosed with 3β-HSD-deficiency, who was treated with glycine-conjugated deoxycholic acid (gDCA).

Results

gDCA treatment successfully restored normal bile acid levels, improved body weight by reducing fat malabsorption, and was well-tolerated with no observed liver problems or side effects.

Conclusions

As a potent FXR ligand, gDCA might exert its action through FXR activation leading to bile acid synthesis regulation.

Cognitive impairment in children and adults with cerebrotendinous xanthomatosis: A French cohort study

Cerebrotendinous xanthomatosis is a rare and treatable metabolic disorder related to the accumulation of cholestanol. This disorder is primarily associated with motor and cognitive impairments, although the latter has not been extensively characterized. The objectives of this work were to define the cognitive profile found in cerebrotendinous xanthomatosis patients, investigate the progression of cognitive impairment over time, and search for radio-clinical correlations. Through a multicentric chart review study, we collected cognitive and radiological data from nine children and eighteen adults with genetically proven cerebrotendinous xanthomatosis. We performed a volumetric and morphological analysis of the brain magnetic resonance imaging. In our cohort, 44% (4/9) of children and 78% (14/18) of adults exhibited cognitive impairment that can be severe. The study revealed a significant impairment in various cognitive domains, specifically executive, attentional, language, and visuo-spatial. Among adults, 16% (3/18) developed dementia after age 50. These three patients had delayed chenodeoxycholic acid treatment and important cerebral atrophy. Besides these three cases of late-onset cognitive decline, Mini-Mental State Evaluation was generally stable, suggesting cognitive impairment due to a neurodevelopmental disorder and persisting in adulthood. Cognitive impairment was less common in children, possibly related to early chenodeoxycholic acid treatment in our cohort. The severity of magnetic resonance imaging abnormalities did not predict cognitive impairment in patients. Overall, in cerebrotendinous xanthomatosis, cognitive impairment can be severe and mainly neurodevelopmental. Early chenodeoxycholic acid treatment might be associated with a reduced risk of cognitive decline.

Genetics of bilateral pediatric cataract in the Israeli and Palestinian populations

PURPOSE

Bilateral pediatric cataract (BPC) is one of the most common causes of childhood visual impairment and blindness worldwide. A significant percentage of pediatric cataracts are caused by genetic alterations. We aim to characterize the set of genes and variants that cause BPC in the Israeli and Palestinian populations and to assess genotype-phenotype correlation.

METHODS

Retrospective study in a multidisciplinary center for visual impairment, located in a tertiary medical center. Medical charts of families who underwent genetic counseling because of BPC in a family member were reviewed. Clinical characteristics and genetic tests results were obtained from medical records of affected subjects.

RESULTS

Twenty-two families (47 patients) underwent genetic counseling and completed genetic testing. Causative variants were identified in 18/22 (81.8%) of the families, including 3 novel variants. Genetic testing used included mainly panel for congenital cataracts and whole exome sequencing. Eleven families performed genetic testing with the intention of future pregnancy planning. Main causative genes identified were crystalline genes followed by transcription factor genes. BCOR gene variants were associated with persistent fetal vasculature (PFV) cataract in two of three families.

CONCLUSIONS

Combined molecular techniques are useful in identifying variants causing pediatric cataracts and showed a high detection rate in our population. BCOR gene variants might be associated with PFV type of cataracts. The study of pathogenic variants may aid in family planning and prevention of pediatric cataracts in future pregnancies. Additionally, in certain cases, it assists in diagnosing non-suspected syndromic types of pediatric cataracts.

Newborn screening for lipid disorders

PURPOSE OF REVIEW

Newborn screening is one of the most successful public health programs of the last century and offers unparalleled access to universal screening for a variety of metabolic and other disorders. Interest in development of newborn screening for lipid disorders has intensified in recent years. Screening newborns for lipid disorders has important implications for the health of the newborn as well as their relatives, and in the case of more common lipid disorders like familial hypercholesterolemia, could have important public health implications.

RECENT FINDINGS

Recent studies have demonstrated feasibility of measuring biomarkers for heterozygous familial hypercholesterolemia from newborn screening dried blood spot specimens. Another lipid disorder, cerebrotendinous xanthomatosis, is currently amenable to newborn screening utilizing currently available assays. New research in next-generation sequencing as a primary screen in newborns will also identify both common and rare lipid disorders in newborns.

SUMMARY

Historically, newborn screening for lipid disorders was not done for many reasons, but new research has developed testing methods that may successfully identify common and rare lipid disorders. This will impact the health of the newborn but could also impact family members and public health.

Chenodeoxycholic acid (CDCA) treatment during pregnancy in women with cerebrotendinous xanthomatosis (CTX): Lessons learned from 19 pregnancies

PURPOSE

Cerebrotendinous xanthomatosis (CTX) is a rare, autosomal recessive bile acid synthesis disorder. Biallelic pathogenic variants in CYP27A1, encoding for sterol 27-hydroxylase, impair cholic acid (CA) and chenodeoxycholic acid (CDCA) synthesis and lead to accumulation of cholestanol and C27 bile alcohols. Treatment with CDCA decreases the accumulation of these harmful metabolites and slows disease progression. Currently, CDCA is contraindicated for use during pregnancy based on animal studies that showed that high-dose CDCA may cause fetal harm when administered to pregnant animals. Data regarding the safety of CDCA treatment in humans are lacking.

METHODS

We present a case series of 19 pregnancies in 9 women with CTX who either received CDCA treatment throughout pregnancy or did not.

RESULTS

In 11 pregnancies where mothers continued CDCA treatment, no complications were reported, and newborns were born at or near full term, with normal birth weight and Apgar scores. In 8 pregnancies where mothers did not receive CDCA, 2 newborns experienced elevated bilirubin soon after birth. One woman who stopped treatment during her pregnancy deteriorated neurologically while off treatment.

CONCLUSION

The data we present support the benefit of continued CDCA treatment in pregnant women with CTX for both the affected women and their offspring.

Malar rash and hand tremor in early symptoms of cerebrotendinous xanthomatosis and the effect of chenodeoxycholic acid on them

BACKGROUND

Cerebrotendinous xanthomatosis (CTX, OMIM #213700) is a rare but treatable lipid storage disease resulting from mutations in the CYP27A1 gene.

PURPOSE

The study aims to evaluate patients diagnosed with CTX and reveal new information, especially about the signs of CTX and patients' response to the treatment.

METHODS

The study was conducted retrospectively in 12 definitively diagnosed CTX patients. The patients' clinical, laboratory, imaging, genetic findings, and chenodeoxycholic acid (CDCA) treatment results were analyzed.

RESULTS

The median age at diagnosis for the patients was 16.5 years (minimum-maximum: 7-32). Juvenile cataracts, detected in more than 90% (11/12) of the patients, were the most common clinical finding. Malar rash, not previously reported in the literature for CTX, was present in 75% (9/12) of the patients. Hand tremors, the first neurological symptom, occurred in adolescence and were the initial symptom of the disease in five patients. Hand tremors were present in 83.3% (10/12) of the patients. Hand tremors (in 5 patients) and malar rash (in 2 patients) were clinical findings with full recovery due to the CDCA treatment.

CONCLUSION

The study defines the malar rash finding, which has not been reported in the literature before, as a possible new clinical finding in CTX disease, attributed to its partial or full recovery with CDCA treatment. Additionally, as a novelty in the literature, our study highlights the full recovery of neurological findings, such as hand tremors, in CTX. Patients presenting with hand tremors and malar rash, especially in adolescence, should undergo CTX investigation for early diagnosis and treatment.

Differential diagnosis between multiple sclerosis and leukodystrophies - A scoping review

Multiple Sclerosis (MS) is an autoimmune demyelinating disease of the central nervous system (CNS) characterized by damage to the myelin sheaths of oligodendrocytes. Currently, there is no specific biomarker to identify the disease; however, a diagnostic criterion has been established based on patient's clinical, laboratory, and imaging characteristics, which assists in identifying this condition. The primary method for diagnosing MS is the McDonald criteria, first described in 2001 and revised in the years 2005, 2012, and 2017. These criteria have been continuously reviewed to enhance specificity and sensitivity in the diagnosis of MS, thereby reducing errors in its differential diagnosis. An important differential diagnosis that shares overlapping features with MS, mainly the progressive forms, are leukodystrophies with demyelination as underlying pathology. Leukodystrophies comprise a rare group of genetically determined disorders that lead to either demyelination or hypomyelination of the central nervous system that can result neuroimaging changes as well as clinical findings similar to those observed in MS. Thus, systematic evaluation encompassing clinical presentation, neuroimaging findings, and laboratory metrics proves indispensable for a differential diagnosis. As such, this study aimed to establish, clearly and objectively, the similarities and differences between MS and the main demyelinating leukodystrophies. The study analyzed the parameters of the McDonald criteria, including clinical, laboratory, and magnetic resonance imaging aspects, as found in patients with leukodystrophies through scoping literature review. The data were compared with the determinations of the revised 2017 McDonald criteria to facilitate the differential diagnosis of these diseases in clinical practice.

Autosomal recessive cerebellar ataxias: a diagnostic classification approach according to ocular features

Autosomal recessive cerebellar ataxias (ARCAs) are a heterogeneous group of neurodegenerative disorders affecting primarily the cerebellum and/or its afferent tracts, often accompanied by damage of other neurological or extra-neurological systems. Due to the overlap of clinical presentation among ARCAs and the variety of hereditary, acquired, and reversible etiologies that can determine cerebellar dysfunction, the differential diagnosis is challenging, but also urgent considering the ongoing development of promising target therapies. The examination of afferent and efferent visual system may provide neurophysiological and structural information related to cerebellar dysfunction and neurodegeneration thus allowing a possible diagnostic classification approach according to ocular features. While optic coherence tomography (OCT) is applied for the parametrization of the optic nerve and macular area, the eye movements analysis relies on a wide range of eye-tracker devices and the application of machine-learning techniques. We discuss the results of clinical and eye-tracking oculomotor examination, the OCT findings and some advancing of computer science in ARCAs thus providing evidence sustaining the identification of robust eye parameters as possible markers of ARCAs.

The 20-Year Diagnostic Odyssey of a Milder Form of Cerebrotendinous Xanthomatosis

Tendinous xanthomas are usually a sign of genetic dyslipidemias and are said to be pathognomonic for familial hypercholesterolemia. However, the differential diagnosis must also include rarer forms of genetic dyslipidemias such as cerebrotendinous xanthomatosis (CTX). In this report, we present the diagnostic odyssey of a French-Canadian patient presenting with Achilles tendon xanthomas and an unusual mild to moderate hypercholesterolemia. Comprehensive biochemical and genetic investigations confirmed the diagnosis of CTX, 20 years after the onset of her first symptoms. We also describe a new variant in the CYP27A1 gene associated with this atypical case and expand the clinical phenotype of this rare genetic condition. CTX is thought to be underdiagnosed, and early diagnosis and treatment of this disease is essential as it has been shown to greatly improve the patient's symptoms and prognosis.

Living with Cerebrotendinous Xanthomatosis: Patient, Caregiver, and Expert Perspectives

In this article, patients with cerebrotendinous xanthomatosis (CTX) and caregivers detail their experience with lifelong symptoms, diagnosis, treatment and efficacy, and ongoing disease management. One patient and four caregivers describe the challenges associated with pursuing a correct diagnosis for years before testing confirmed a CTX diagnosis. They also detail their ongoing struggles and desire for greater access to physicians with CTX knowledge and to reliable online resources to continue their education about the disease and strategies for symptom management. The expert perspective is a direct response by three CTX researchers, including physicians who are treating patients with CTX in the United States and experts whose laboratories provide genetic and biochemical testing for CTX. They respond to many of the patient and caregiver concerns, including steps that are being taken to identify CTX earlier and provide access to confirmatory diagnostic testing sooner, and suggest the best online resources for CTX-related information and access to webinars and support groups. While the expert perspective is a direct response to the patient and caregiver authors' CTX journeys, it should be beneficial to any patient with CTX or their caregivers.

Cerebrotendinous Xanthomatosis, a Treatable Disorder Often Missed: Case Series of Three Patients Confirmed by Genetic Testing

ABSTRACT

Cerebrotendinous xanthomatosis (CTX) is a treatable autosomal recessive disorder with varied clinical manifestations and age of onset and is often diagnosed late. We report three cases of CTX who presented at our center with clinical features of frequent diarrhea, early cataracts, xanthomas, cognitive decline, ataxia, neuropathy, and other manifestations of CTX. Magnetic resonance imaging (MRI) brain in all three patients revealed abnormalities consistent with CTX. Diagnosis was confirmed by next-generation sequencing. Chenodeoxycholic acid (CDCA) is recommended as the drug of choice, as it can halt the disease progression and reverse some of the symptoms. In addition to late diagnosis, nonavailability of CDCA in our part of world adds to the problem of management of such patients; therefore, they are often started on alternative therapies, which are less effective.

A case of cerebrotendinous xanthomatosis with massive xanthomas but without a considerable increase in serum cholestanol levels

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disorder caused by mutations in the sterol 27-hydroxylase gene (CYP27A1). Due to the deficiency of 27-hydroxylase, the synthesis of bile acids from cholesterol is impaired and excessive cholestanol accumulates in various tissues, such as the central nervous system, tendons, and lenses. Patients with CTX typically manifest intellectual decline, pyramidal tract symptoms, cerebellar symptoms, tendon xanthomas, juvenile cataracts, neonatal jaundice, chronic diarrhea, osteoporosis, and premature cardiovascular disease. Here, we report the atypical case of a 35-year-old female with CTX having massive xanthomas but without a considerable increase in serum cholestanol levels (3.9 µg/mL). In the differential diagnosis of xanthoma, CTX should not be ruled out even if the serum levels of cholestanol are not high, and genetic testing is necessary to make the appropriate diagnosis.

Characterization of Postprandial Bile Acid Profiles and Glucose Metabolism in Cerebrotendinous Xanthomatosis

Cerebrotendinous xanthomatosis (CTX) is a rare inherited disease characterized by sterol 27-hydroxylase (CYP27A1) deficiency and, thus, a lack of bile acid synthesis with a marked accumulation of 7α-hydroxylated bile acid precursors. In addition to their renowned lipid-emulgating role, bile acids have been shown to stimulate secretion of the glucose-lowering and satiety-promoting gut hormone glucagon-like peptide 1 (GLP-1). In this paper, we examined postprandial bile acid, glucose, insulin, GLP-1 and fibroblast growth factor 19 (FGF19) plasma profiles in patients with CTX and matched healthy controls. Seven patients and seven age, gender and body mass index matched controls were included and subjected to a 4 h mixed meal test with regular blood sampling. CTX patients withdrew from chenodeoxycholic acid (CDCA) and statin therapy three weeks prior to the test. Postprandial levels of total bile acids were significantly lower in CTX patients and consisted of residual CDCA with low amounts of ursodeoxycholic acid (UDCA). The postprandial plasma glucose peak concentration occurred later in CTX patients compared to controls, and patients' insulin levels remained elevated for a longer time. Postprandial GLP-1 levels were slightly higher in CTX subjects whereas postprandial FGF19 levels were lower in CTX subjects. This novel characterization of CTX patients reveals very low circulating bile acid levels and FGF19 levels, aberrant postprandial glucose and insulin profiles, and elevated postprandial GLP-1 responses.

Treatment of cerebrotendinous xanthomatosis in pregnancy: Patient and physician perspectives

Cerebrotendinous xanthomatosis (CTX) is a rare, autosomal recessive disorder of bile acid synthesis that presents with varied and progressive symptomology. Early treatment with chenodeoxycholic acid (CDCA) improves symptoms and slows degeneration. Patients with CTX are commonly recommended to discontinue CDCA treatment during pregnancy because of theoretical risks to the fetus, but patient and clinician concerns about the risks of stopping treatment cause uncertainty. Herein, we report the experiences and perspectives of two women with CTX from the time of diagnosis through pregnancy, as well as decisions regarding CDCA treatment during pregnancy. Before becoming pregnant, both women were concerned about potential risks to their newborns if they continued or stopped CDCA treatment during pregnancy. Reassurance from their CTX specialist was the primary factor in their decision to continue treatment during pregnancy. After pregnancies complicated by preeclampsia, one gave birth to a healthy infant and the other gave birth to an infant later diagnosed with periventricular leukomalacia. Neither experienced CDCA-related complications.

Psychosis Caused by a Somatic Condition: How to Make the Diagnosis? A Systematic Literature Review

BACKGROUND

First episode of psychosis (FEP) is a clinical condition that usually occurs during adolescence or early adulthood and is often a sign of a future psychiatric disease. However, these symptoms are not specific, and psychosis can be caused by a physical disease in at least 5% of cases. Timely detection of these diseases, the first signs of which may appear in childhood, is of particular importance, as a curable treatment exists in most cases. However, there is no consensus in academic societies to offer recommendations for a comprehensive medical assessment to eliminate somatic causes.

METHODS

We conducted a systematic literature search using a two-fold research strategy to: (1) identify physical diseases that can be differentially diagnosed for psychosis; and (2) determine the paraclinical exams allowing us to exclude these pathologies.

RESULTS

We identified 85 articles describing the autoimmune, metabolic, neurologic, infectious, and genetic differential diagnoses of psychosis. Clinical presentations are described, and a complete list of laboratory and imaging features required to identify and confirm these diseases is provided.

CONCLUSION

This systematic review shows that most differential diagnoses of psychosis should be considered in the case of a FEP and could be identified by providing a systematic checkup with a laboratory test that includes ammonemia, antinuclear and anti-NMDA antibodies, and HIV testing; brain magnetic resonance imaging and lumbar puncture should be considered according to the clinical presentation. Genetic research could be of interest to patients presenting with physical or developmental symptoms associated with psychiatric manifestations.

Prevalence of cerebrotendinous xanthomatosis among patients diagnosed with early-onset idiopathic bilateral cataracts: final analysis

Cerebrotendinous xanthomatosis (CTX) is a rare, autosomal recessive bile acid synthesis disorder caused by pathologic variants in CYP27A1, a gene involved in bile acid synthesis. Impaired function in this gene leads to accumulation of plasma cholestanol (PC) in various tissues, often in early childhood, resulting in such clinical signs as infantile diarrhea, early-onset bilateral cataracts, and neurological deterioration. The current study aimed to identify cases of CTX in a population of patients with a greater CTX prevalence than the general population, to facilitate early diagnosis. Patients diagnosed with early-onset, apparently idiopathic, bilateral cataracts between the ages of 2 and 21 years were enrolled. Genetic testing of patients with elevated PC and urinary bile alcohol (UBA) levels was used to confirm CTX diagnosis and determine CTX prevalence. Of 426 patients who completed the study, 26 met genetic testing criteria (PC ≥ 0.4 mg/dL and positive UBA test), and 4 were confirmed to have CTX. Prevalence was found to be 0.9% in enrolled patients, and 15.4% in patients who met the criteria for genetic testing.

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.

Chenodeoxycholic acid rescues axonal degeneration in induced pluripotent stem cell-derived neurons from spastic paraplegia type 5 and cerebrotendinous xanthomatosis patients

BACKGROUND

Biallelic mutations in CYP27A1 and CYP7B1, two critical genes regulating cholesterol and bile acid metabolism, cause cerebrotendinous xanthomatosis (CTX) and hereditary spastic paraplegia type 5 (SPG5), respectively. These rare diseases are characterized by progressive degeneration of corticospinal motor neuron axons, yet the underlying pathogenic mechanisms and strategies to mitigate axonal degeneration remain elusive.

METHODS

To generate induced pluripotent stem cell (iPSC)-based models for CTX and SPG5, we reprogrammed patient skin fibroblasts into iPSCs by transducing fibroblast cells with episomal vectors containing pluripotency factors. These patient-specific iPSCs, as well as control iPSCs, were differentiated into cortical projection neurons (PNs) and examined for biochemical alterations and disease-related phenotypes.

RESULTS

CTX and SPG5 patient iPSC-derived cortical PNs recapitulated several disease-specific biochemical changes and axonal defects of both diseases. Notably, the bile acid chenodeoxycholic acid (CDCA) effectively mitigated the biochemical alterations and rescued axonal degeneration in patient iPSC-derived neurons. To further examine underlying disease mechanisms, we developed CYP7B1 knockout human embryonic stem cell (hESC) lines using CRISPR-cas9-mediated gene editing and, following differentiation, examined hESC-derived cortical PNs. Knockout of CYP7B1 resulted in similar axonal vesiculation and degeneration in human cortical PN axons, confirming a cause-effect relationship between gene deficiency and axonal degeneration. Interestingly, CYP7B1 deficiency led to impaired neurofilament expression and organization as well as axonal degeneration, which could be rescued with CDCA, establishing a new disease mechanism and therapeutic target to mitigate axonal degeneration.

CONCLUSIONS

Our data demonstrate disease-specific lipid disturbances and axonopathy mechanisms in human pluripotent stem cell-based neuronal models of CTX and SPG5 and identify CDCA, an established treatment of CTX, as a potential pharmacotherapy for SPG5. We propose this novel treatment strategy to rescue axonal degeneration in SPG5, a currently incurable condition.

The Management of Hypercholesterolemia in Patients with Neuromuscular Disorder

PURPOSE OF REVIEW

We describe and discuss the safety of statins and non-statin drugs in neuromuscular disorders (NMDs). We also propose a pragmatic model of care for the management of such cases.

RECENT FINDINGS

Patients with both NMD and hypercholesterolemia may be particularly disadvantaged owing to the toxic effects of cholesterol-lowering therapy and the inability to take medication. Specifically, the management of hypercholesterolemia in patients with NMD is complicated by the increased risk of statin-related myotoxicity and concerns that statins may aggravate or possibly induce the onset of a specific NMD. The most severe form of statin-related myotoxicity is immune-mediated necrotizing myopathy. Management of hypercholesterolemia in patients with NMDs include treating modifiable factors, consideration of toxicity risk of statin, use of non-statin lipid lowering agents, noting possible drug interactions, and careful monitoring.

Allelic prevalence and geographic distribution of cerebrotendinous xanthomatosis

BACKGROUND

Cerebrotendinous xanthomatosis (CTX) is a rare recessive genetic disease characterized by disruption of bile acid synthesis due to inactivation of the CYP27A1 gene. Treatment is available in the form of bile acid replacement. CTX is likely underdiagnosed, and prevalence estimates based on case diagnosis are probably inaccurate. Large population-based genomic databases are a valuable resource to estimate prevalence of rare recessive diseases as an orthogonal unbiased approach building upon traditional epidemiological studies.

METHODS

We leveraged the Hardy-Weinberg principle and allele frequencies from gnomAD to calculate CTX prevalence. ClinVar and HGMD were used to identify high-confidence pathogenic missense variants and to calculate a disease-specific cutoff. Variant pathogenicity was also assessed by the VarSome implementation of the ACMG/AMP algorithm and the REVEL in silico predictor.

RESULTS

CTX prevalence estimates were highest in Asians (1:44,407-93,084) and lowest in the Finnish population (1:3,388,767). Intermediate estimates were found in Europeans, Americans, and Africans/African Americans (1:70,795-233,597). The REVEL-predicted pathogenic variants accounted for a greater increase in prevalence estimates for Europeans, Americans, and Africans/African Americans compared with Asians. We identified the most frequent alleles designated pathogenic in ClinVar (p.Gly472Ala, p.Arg395Cys), labeled pathogenic based on sequence consequence (p.Met1?), and predicted to be pathogenic by REVEL (p.Met383Lys, p.Arg448His) across populations. Also, we provide a prospective geographic map of estimated disease distribution based on CYP27A1 variation queries performed by healthcare providers from selected specialties.

CONCLUSIONS

Prevalence estimates calculated herein support and expand upon existing evidence indicating underdiagnosis of CTX, suggesting that improved detection strategies are needed. Increased awareness of CTX is important for early diagnosis, which is essential for patients as early treatment significantly slows or prevents disease progression.

Newborn screening for Cerebrotendinous Xanthomatosis: A retrospective biomarker study using both flow-injection and UPLC-MS/MS analysis in 20,000 newborns

BACKGROUND AND AIMS

Cerebrotendinous Xanthomatosis (CTX) is a treatable disorder of bile acid synthesis caused by deficiency of 27-sterol hydroxylase -encoded by CYP27A1- leading to gastrointestinal and progressive neuropsychiatric symptoms. Biochemically, CTX is characterized by accumulation of the bile alcohol cholestanetetrol glucuronide (GlcA-tetrol) and the deficiency of tauro-chenodeoxycholic acid (t-CDCA) and tauro-trihydroxycholestanoic acid (t-THCA).

MATERIALS AND METHODS

To ascertain the feasibility of CTX newborn screening (NBS) we performed a study with deidentified Dutch dried blood spots using reagents and equipment that is frequently used in NBS laboratories. 20,076 deidentified newborn blood spots were subjected to flow-injection (FIA)-MS/MS and UPLC-MS/MS analysis to determine the concentration of GlcA-tetrol and calculate the GlcA-tetrol/t-CDCA and t-THCA/GlcA-tetrol ratios.

RESULTS

Using UPLC-MS/MS analysis both GlcA-tetrol concentration and/or metabolite ratios GlcA-tetrol/t-CDCA proved to be informative biomarkers; newborn DBS results did not overlap with those of the CTX patients. For FIA-MS/MS, GlcA-tetrol also was an excellent marker but when using the combination of the GlcA-tetrol/t-CDCA and t-THCA/GlcA-tetrol ratios also did not yield any screen positives.

CONCLUSION

Newborn screening for CTX using only metabolite ratios following the measurement of three CTX biomarkers is possible using either FIA-MS/MS or UPLC-MS/MS, which paves the way for introduction of CTX NBS.

A Rare Case of Cerebrotendinous Xanthomatosis Associated With a Mutation on COG8 Gene

Cerebrotendinous xanthomatosis (CTX) is a rare hereditary disease described by a mutation in the CYP27A1 gene, which encodes the sterol 27-hydroxylase enzyme involved in the synthesis of bile acid. Accumulation of cholesterol and its metabolite, cholestanol, in multiple body organs causes the symptoms of this disease. In addition, a mutation in the COG8 gene, which encodes a subunit of conserved oligomeric Golgi (COG) complex, causes another rare disorder attributed to type IIh of congenital disorder of glycosylation (CDG). We described a rare case of CTX disorder associated with a mutation on COG8 gene, which presented by unusual symptoms.

Cerebrotendinous Xanthomatosis: Report of Two Siblings With the Same Mutation but Variable Presentation

Cerebrotendinous xanthomatosis (CTX), also known as CTX, is an extremely rare bile acid metabolic disorder caused by mutations in the cytochrome P450 family 27 subfamily A member 1 (CYP27A1) gene. This genetic disease is inherited in an autosomal recessive manner, and it affects the enzyme sterol 27-hydroxylase, which is involved in the bile acid metabolic process. It is distinguished by diarrhoea in infancy, early juvenile cataract, tendon xanthomas in adolescence, and progressive neuropsychiatric dysfunction in adulthood. So far, India has reported eight genetically confirmed cases. We present two cases of CTX among siblings in a family. The elder sibling was initially diagnosed, and after reviewing his family history and performing a thorough clinical examination, we discovered a similar manifestation in his younger sibling. Genetic testing on the siblings revealed similar mutations at exon 2 of the CYP27A1 gene. If a pathogenic mutation is discovered in a family member, prenatal and preimplantation genetic testing, as well as childhood screening, are the options. These screening strategies will prevent the onset of neuropsychiatric manifestations and disability.

Cerebrotendinous Xanthomatosis: A practice review of pathophysiology, diagnosis, and treatment

Cerebrotendinous Xanthomatosis represents a rare and underdiagnosed inherited neurometabolic disorder due to homozygous or compound heterozygous variants involving the CYP27A1 gene. This bile acid metabolism disorder represents a key potentially treatable neurogenetic condition due to the wide spectrum of neurological presentations in which it most commonly occurs. Cerebellar ataxia, peripheral neuropathy, spastic paraparesis, epilepsy, parkinsonism, cognitive decline, intellectual disability, and neuropsychiatric disturbances represent some of the most common neurological signs observed in this condition. Despite representing key features to increase diagnostic index suspicion, multisystemic involvement does not represent an obligatory feature and can also be under evaluated during diagnostic work-up. Chenodeoxycholic acid represents a well-known successful therapy for this inherited metabolic disease, however its unavailability in several contexts, high costs and common use in patients at late stages of disease course limit more favorable neurological outcomes for most individuals. This review article aims to discuss and highlight the most recent and updated knowledge regarding clinical, pathophysiological, neuroimaging, genetic and therapeutic aspects related to Cerebrotendinous Xanthomatosis.

Prospective cholestanol screening of cerebrotendinous xanthomatosis among patients with juvenile-onset unexplained bilateral cataracts

BACKGROUND

Cerebrotendinous xanthomatosis (CTX) is a rare genetic disorder related to CYP27A1 biallelic mutations, leading to decreased synthesis of bile acids and increased cholestanol. Juvenile bilateral cataracts are one of the most common findings in the disease, frequently occurring before the onset of neurological manifestations. While early treatment with chenodeoxycholic acid can prevent the onset of neurological impairment, poor awareness of CTX accounts for a markedly delayed diagnosis. The objective of this study was to evaluate the utility of plasma cholestanol analysis at the moment of cataract diagnosis and before the onset of neurological impairment in CTX.

METHODS

Multicenter prospective cohort study of patients with juvenile-onset unexplained bilateral cataracts recruited from seven French ophthalmology departments. Plasma cholestanol analysis was performed at diagnosis from January 2018 to January 2020. CYP27A1 genetic testing was performed at the ophthalmologist's discretion. Cholestanol levels were compared with those of a similar population of patients without cataracts (control cohort).

RESULTS

30 patients were finally recruited, with a mean age at cataract diagnosis of 7.1 years (± 4.8 SD, range 1-19 years). One patient had a very high cholestanol level (68 μmol/L, reference < 10) and carried two pathogenic heterozygous mutations in CYP27A1 confirming CTX. This patient was a 19-year-old female, reporting chronic diarrhea only in childhood, and diagnosed with bilateral posterior cataracts with cortical fleck-like opacities. Therefore, the incidence of CTX in our cohort of patients was 3.3%. Five further patients (5/29; 17.2%) had moderate elevations of cholestanol level (between 10.3 and 16.5 μmol/L), compared to 12/286 (4.2%) in the control cohort (p = 0.014) after adjustment for age.

CONCLUSION

Our study argue for the relevance of plasma cholestanol CTX screening in all patients with juvenile-onset unexplained cataracts, even without other CTX identified manifestations. Whether moderate elevations of plasma cholestanol unrelated to CTX may be a risk factor for bilateral cataracts occurrence needs further examination.

Lipid disorders in children: diagnosis and treatment

Cardiovascular disease is a leading cause of death in western countries and pediatric lipid disorders create a lifelong continuous risk that starts from childhood. Increased knowledge and awareness on these disorders could prove to be life saving for many patients.

Childhood-onset hereditary spastic paraplegia and its treatable mimics

Early-onset forms of hereditary spastic paraplegia and inborn errors of metabolism that present with spastic diplegia are among the most common "mimics" of cerebral palsy. Early detection of these heterogenous genetic disorders can inform genetic counseling, anticipatory guidance, and improve outcomes, particularly where specific treatments exist. The diagnosis relies on clinical pattern recognition, biochemical testing, neuroimaging, and increasingly next-generation sequencing-based molecular testing. In this short review, we summarize the clinical and molecular understanding of: 1) childhood-onset and complex forms of hereditary spastic paraplegia (SPG5, SPG7, SPG11, SPG15, SPG35, SPG47, SPG48, SPG50, SPG51, SPG52) and, 2) the most common inborn errors of metabolism that present with phenotypes that resemble hereditary spastic paraplegia.

Clinical, electrophysiological, and genetic characteristics of cerebrotendinous xanthomatosis in South Korea

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive lipid storage disorder caused by 27-hydroxylase deficiency. We report the clinical characteristics of six Korean CTX patients. The median age of onset was 22.5 years, the median age at diagnosis was 42 years, and the diagnostic delay was 18.1 years. The most common clinical symptoms were tendon xanthoma and spastic paraplegia. Four of five patients exhibited latent central conduction dysfunction. All patients carried the same mutation in CYP27A1 (c.1214 G>A [p.R405Q]). CTX is a treatable neurodegenerative disorder; however, our results revealed that patients with CTX in Korea might receive the diagnosis after a prolonged delay.    .

The Inherited Hypercholesterolemias

Inherited hypercholesterolemias include monogenic and polygenic disorders, which can be very rare (eg, cerebrotendinous xanthomatosis (CTX)) or relatively common (eg, familial combined hyperlipidemia [FCH]). In this review, we discuss familial hypercholesterolemia (FH), FH-mimics (eg, polygenic hypercholesterolemia [PH], FCH, sitosterolemia), and other inherited forms of hypercholesterolemia (eg, hyper-lipoprotein(a) levels [hyper-Lp(a)]). The prevalence, genetics, and management of inherited hypercholesterolemias are described and selected guidelines summarized.

CYP27A1 mutation in a case of cerebrotendinous xanthomatosis: A case report

BACKGROUND

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive metabolic disease caused by mutations in CYP27A1. It has a low incidence rate, insidious onset, and diverse clinical manifestations. It can be easily misdiagnosed and can go unrecognized by clinicians, leading to delayed treatment and worsened patient outcomes.

CASE SUMMARY

A 38-year-old male was admitted to our hospital with a history of unabating unstable posture and difficulty in walking for more than 30 years. Subsequently based on the patient's medical history, clinical symptoms, magnetic resonance imaging and gene sequencing results, he was finally diagnosed with CTX. Due to the low incidence rate of the disease, clinicians have insufficient knowledge of it, which makes the diagnosis process more tortuous and prolongs the diagnosis time.

CONCLUSION

Prompt diagnosis and treatment of CTX improve patient outcomes.

Differing clinical features between Japanese siblings with cerebrotendinous xanthomatosis with a novel compound heterozygous CYP27A1 mutation: a case report

Background

Cerebrotendinous xanthomatosis (CTX) is an autosomal-recessive lipid storage disorder caused by mutations in the CYP27A1 gene encoding the key enzyme in the bile acid synthesis, sterol 27-hydroxylase. Here, we report two Japanese CTX siblings with a novel compound heterozygous CYP27A1 mutation, showing different clinical phenotypes and responses to chenodeoxycholic acid (CDCA) therapy.

Case presentation

The proband, a 32-year-old man, who had chronic diarrhea, bilateral cataracts, and xanthomas, demonstrated progressive neurological manifestations including ataxia, and spastic paraplegia during a 5-year follow-up period despite normalization of serum cholestanol after initiation of CDCA treatment. He also exhibited cognitive decline although improvement had been observed at the beginning of treatment. Follow-up brain magnetic resonance imaging (MRI) revealed pronounced progressive atrophy in the cerebellum, in addition to expanding hyperintense lesions in the dentate nuclei, posterior limb of the internal capsule, cerebral peduncles, and inferior olives on T2-weighted images. In contrast, the two-year-younger sister of the proband presented with chronic diarrhea, cataracts, xanthomas, and intellectual disability but no other neurological symptoms at the time of diagnosis. CDCA treatment lead to improvement of cognitive function and there were no characteristic CTX-related MRI features during the follow-up period. The siblings shared a paternally inherited c.1420C > T mutation (p.Arg474Trp) and a maternally inherited novel c.1176_1177delGA mutation, predicting p.(Glu392Asp*20).

Conclusions

Our cases suggest that early diagnosis and subsequent initiation of CDCA treatment are crucial before the appearance of characteristic MRI findings and severe neurological manifestations related to CTX. Further studies are required to elucidate mechanisms responsible for the clinical diversity of CTX and prognostic factors for long-term outcomes following initiation of CDCA treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02711-4.

Movement Disorders and the Gut: A Review

There is a close link between multiple movement disorders and gastrointestinal dysfunction. Gastrointestinal symptoms may precede the development of the neurologic syndrome or may arise following the neurologic presentation. This review will provide an overview of gastrointestinal accompaniments to several well-known as well as lesser known movement disorders. It will also highlight several disorders which may not be considered primary movement disorders but have an overlapping presentation of both gastrointestinal and movement abnormalities.

Patents vs patients 1-0: The case of chenodeoxycholic acid

Profit-driven games with the availability and prices of chenodeoxycholic acid led to the discontinuation of proper treatment for this cerebrotendinous xanthomatosis patient with disastrous consequences to his health.

Rapidly progressive dementia and intractable diarrhea: a teaching case report and a systematic review of cognitive impairment in Whipple’s disease

Objective

Methods

Results

Conclusions

Supplementary Information

Analysis of CYP27A1 mutations in Han Chinese women with intrahepatic cholestasis of pregnancy

OBJECTIVE

To explore the cytochrome P450 family 27 subfamily A member 1 (CYP27A1) gene mutations in Chinese women with intrahepatic cholestasis of pregnancy (ICP) and the correlation between CYP27A gene mutations and BA (bile acid) level changes.

METHODS

In this study, the entire coding region of the CYP27A1 gene was sequenced in 151 Han Chinese women with ICP and 1029 matched samples, and the pathogenicity of identified CYP27A1 gene mutations was judged through evolutionary conservation analysis, computational analysis and protein structure modeling. Finally, we verified the relationship between gene mutations and total serum bile acid (TBA) and cholesterol (CHOL) levels through experiments in cell culture.

RESULTS

We identified five heterozygous CYP27A1 missense mutations in five ICP samples. Three online tools, Polyphen-2, MutationTaster and SIFT, predicted that the five CYP27A1 mutations were pathogenic. Furthermore, all five mutations caused marked protein structural changes. Experiments in cells showed that the intracellular and medium levels of TBA in the mutant groups were lower than those in the wild-type group, while the CHOL levels were higher in all mutants except for the R158H mutant.

CONCLUSIONS

CYP27A1 mutations are associated with the levels of TBA and CHOL, suggesting that CYP27A1 mutations contribute to abnormal total cholesterol and BA levels, which leads to ICP.

ADHD symptoms in neurometabolic diseases: Underlying mechanisms and clinical implications

Neurometabolic diseases (NMDs) are typically caused by genetic abnormalities affecting enzyme functions, which in turn interfere with normal development and activity of the nervous system. Although the individual disorders are rare, NMDs are collectively relatively common and often lead to lifelong difficulties and high societal costs. Neuropsychiatric manifestations, including ADHD symptoms, are prominent in many NMDs, also when the primary biochemical defect originates in cells and tissues outside the nervous system. ADHD symptoms have been described in phenylketonuria, tyrosinemias, alkaptonuria, succinic semialdehyde dehydrogenase deficiency, X-linked ichthyosis, maple syrup urine disease, and several mitochondrial disorders, but are probably present in many other NMDs and may pose diagnostic and therapeutic challenges. Here we review current literature linking NMDs with ADHD symptoms. We cite emerging evidence that many NMDs converge on common neurochemical mechanisms that interfere with monoamine neurotransmitter synthesis, transport, metabolism, or receptor functions, mechanisms that are also considered central in ADHD pathophysiology and treatment. Finally, we discuss the therapeutic implications of these findings and propose a path forward to increase our understanding of these relationships.

First case series of Polish patients with cerebrotendinous xanthomatosis and systematic review of cases from the 21st century

Cerebrotendinous xanthomatosis (CTX) is an inborn error of metabolism caused by recessive variants in the cytochrome P450 CYP27A1 gene. CTX is said to manifest with childhood-onset chronic diarrhea and the classic triad of juvenile-onset cataracts, Achilles tendons xanthomas, and progressive ataxia. It is currently one of the few inherited neurometabolic disorders amenable to a specific treatment. The diagnosis may be significantly delayed resulting in permanent neurological impairment. A retrospective review of the clinical characteristics and diagnostic findings in case series of six Polish patients with CTX. Additional retrospective review of symptoms and pathogenic variants of 568 CTX available cases and case series from the past 20 years. To the best of our knowledge, this is the widest review of CTX cases reported in years 2000-2021. We report the largest cohort of Polish patients ever published, with the identification of two hot-spot mutations. During the review of available 568 cases, we found significant differences in the clinical phenotypes and the localization of variants within the gene between Asian and non-Asian populations. These findings may facilitate molecular testing in the Polish and Asian populations. Invariably better screening for CTX and wider awareness is needed.

Pharmacy Compounded Medicines for Patients With Rare Diseases: Lessons Learned From Chenodeoxycholic Acid and Cholic Acid

Patients with rare diseases are often confronted with the fact that effective medicines are unavailable or simply not being developed. This situation jeopardizes the health of a large population of vulnerable patients with rare diseases. Pharmacy compounded formulations can provide a safe alternative when authorized treatments are unavailable or unsuitable. Practical guidelines on how to develop and implement pharmacy compounded formulations for patients with rare diseases are limited. The aim of this article is to provide guidance for when and how to apply pharmacy compounded formulations for patients with rare diseases. This is illustrated with two challenging examples: the development and implementation of pharmacy compounding of 1) chenodeoxycholic acid (CDCA) capsules for patients with cerebrotendinous xanthomatosis (CTX) and 2) cholic acid (CA) capsules for patients with rare bile acid synthesis defects (BASD). All critical steps of the development of CDCA and CA capsules are explained and summarized in a practical guideline.

Prevalence of cerebrotendinous xanthomatosis in cases with idiopathic bilateral juvenile cataract in ophthalmology clinics in Turkey

PURPOSE

To determine the prevalence of cerebrotendinous xanthomatosis (CTX) in patients with idiopathic bilateral juvenile cataract in Turkey.

METHODS

In this multicenter, epidemiologic observational study, patients with idiopathic bilateral juvenile cataract (aged ≥1 year at study entry) were identified from the records of 31 ophthalmology clinics. The Mignarri suspicion index determined in all potential CTX patients; blood samples were collected, and genetic testing for CYP27A1 gene mutation was performed. Cholestanol levels of the patients were measured, and those with a level of ≥3.75 μg/mL (threshold value) underwent genetic testing for mutations in the CYP27A1 gene.

RESULTS

CTX was diagnosed in 7 of 452 patients (1.55%) with bilateral juvenile cataract. There was no significant difference between patients with a Mignarri score of <100 (n = 8) and those with a score of ≥100 (n = 19) with respect to cholestanol levels and genetic test results. Genetic testing was undertaken in 27 patients based on elevated cholestanol levels. Of these 27, 7 (26%) had CYP27A1 gene mutations. Of these 7 patients with genetically confirmed CTX, 5 (71%) were in the group with higher Mignarri score (≥100).

CONCLUSIONS

CTX is a treatable condition, and early detection is crucial for avoiding irreversible neurological manifestations. Screening using the Mignarri suspicion index and cholestanol blood levels can be helpful in identifying suspected cases of CTX.

A Practical Approach to Early-Onset Parkinsonism

Early-onset parkinsonism (EO parkinsonism), defined as subjects with disease onset before the age of 40 or 50 years, can be the main clinical presentation of a variety of conditions that are important to differentiate. Although rarer than classical late-onset Parkinson’s disease (PD) and not infrequently overlapping with forms of juvenile onset PD, a correct diagnosis of the specific cause of EO parkinsonism is critical for offering appropriate counseling to patients, for family and work planning, and to select the most appropriate symptomatic or etiopathogenic treatments. Clinical features, radiological and laboratory findings are crucial for guiding the differential diagnosis. Here we summarize the most important conditions associated with primary and secondary EO parkinsonism. We also proposed a practical approach based on the current literature and expert opinion to help movement disorders specialists and neurologists navigate this complex and challenging landscape.

Using fiber tractography and diffusion kurtosis imaging to evaluate neuroimaging changes in patients with cerebrotendinous xanthomatosis after stopping chenodeoxycholic acid treatment for three years

BACKGROUND

The aim of this study was to use tractography and diffusion kurtosis imaging (DKI) to evaluate cerebral white matter (WM) changes in patients with cerebrotendinous xanthomatosis (CTX) after stopping chenodeoxycholic acid (CDCA) treatment.

MATERIAL AND METHODS

Two siblings with CTX aged 40 and 38 years, respectively, who had been diagnosed with CTX for 16 years were enrolled. They had received CDCA treatment from 2005 until 2015, after which CDCA was no longer available in Taiwan. Serial brain magnetic resonance imaging (MRI) studies were used to record brain changes, and a series of neuropsychiatric tests were used to evaluate cognitive changes 3 years after stopping CDCA treatment.

RESULTS

The conventional MRI studies revealed progressive changes in dentate nuclei and surrounding cerebellar hemispheres, but no obvious changes in cerebral white matter (WM). Tractography captured in 2018 showed a general reduction in fiber density, especially involving frontal lobe fibers, compared to 2015. In addition, the DKI studies performed in 2018 showed a decreased axonal water fraction in diffuse WM structures and increased RadEAD in frontal WM. Comparisons of the neuropsychiatric test results between 2015 and 2018 showed a marked decline in executive function including design fluency, digit backward span and digit forward span, and this cognitive impairment highly suggested frontal lobe dysfunction.

CONCLUSIONS

This study may suggest that cerebral tractography and DKI study results can identify changes in cerebral WM in CTX patients shortly after stopping CDCA treatment, and that they may have a better correlation with the results of neuropsychiatric tests.

Gene supplementation of CYP27A1 in the liver restores bile acid metabolism in a mouse model of cerebrotendinous xanthomatosis

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive disease caused by mutations in the CYP27A1 gene, encoding the sterol 27-hydroxylase. Disruption of the bile acid biosynthesis pathway and accumulation of toxic precursors such as cholestanol cause chronic diarrhea, bilateral juvenile cataracts, tissue deposition of cholestanol and cholesterol (xanthomas), and progressive motor/neuropsychiatric alterations. We have evaluated the therapeutic potential of adeno-associated virus (AAV) vectors expressing CYP27A1 in a CTX mouse model. We found that a vector equipped with a strong liver-specific promoter (albumin enhancer fused with the α1 anti-trypsin promoter) is well tolerated and shows therapeutic effect at relatively low doses (1.5 × 10¹² viral genomes [vg]/kg), when less than 20% of hepatocytes overexpress the transgene. This vector restored bile acid metabolism and normalized the concentration of most bile acids in plasma. By contrast, standard treatment (oral chenodeoxycholic acid [CDCA]), while reducing cholestanol, did not normalize bile acid composition in plasma and resulted in supra-physiological levels of CDCA and its derivatives. At the transcriptional level, only the vector was able to avoid the induction of xenobiotic-induced pathways in mouse liver. In conclusion, the overexpression of CYP27A1 in a fraction of hepatocytes using AAV vectors is well tolerated and provides full metabolic restoration in Cyp27a1^−/− mice. These features make gene therapy a feasible option for the etiological treatment of CTX patients.