Clinical, biochemical, and molecular insights into Cerebrotendinous Xanthomatosis: A nationwide study of 100 Turkish individuals.

OBJECTIVE: Cerebrotendinous xanthomatosis (CTX) is an inherited metabolic disorder characterized by progressive neurologic and extraneurologic findings. The aim of this retrospective, descriptive study was to explore the time of presentation and diagnosis, and to expand the phenotype and genotype of CTX, based on a nationwide and comprehensive series of patients in Turkey. METHODS: The demographic, clinical, biochemical and genotypic characteristics of the CTX patients were reviewed. Data on molecular analysis, age of onset and diagnosis, diagnostic delay, neurologic and extraneurologic symptomatology, results of plasma cholestanol levels, brain magnetic resonance imaging and electromyography at the time of diagnosis were reviewed. RESULTS: 100 confirmed CTX patients from 72 families were included. The mean age at diagnosis was 28.16 ± 14.28 years, and diagnostic delay was 18.39 ± 13.71 years. 36 patients were diagnosed in childhood. Frequency of intention tremor (p = 0.069), peripheral neuropathy (p = 0.234) and psychiatric manifestations (p = 0.396) did not differ between two groups, demonstrating the high rate in pediatric patients. Three adult patients showed a milder phenotype without neurologic involvement. Seven patients had normal plasma cholestanol levels despite neurological impairment. Sequencing of the CYP27A1 gene revealed 25 different variants, with a novel c.671_672del variant not previously described in literature. CONCLUSION: Based on the observations of this Turkish CTX cohort, it is emphasized that the true prevalence of CTX is probably underestimated and that it has a wide spectrum of clinical phenotypes even without neurological impairment. In children, abnormal cerebellar findings, peripheral neuropathy and psychiatric findings associated with intellectual disability have been suggested as warning signs to avoid diagnostic delay. In cases of clinical suspicion, molecular analysis is recommended despite normal plasma cholestanol levels, as severe neurologic involvement may occur in CTX patients without elevated cholestanol levels.

Clinicogenetic characterization of cerebrotendinous xanthomatosis in Brazil.

There are few cerebrotendineous xanthomatosis (CTX) case series and observational studies including a significant number of Latin American patients. We describe a multicenter Brazilian cohort of patients with CTX highlighting their clinical phenotype, recurrent variants and assessing possible genotype-phenotype correlations. We analyzed data from all patients with clinical and molecular or biochemical diagnosis of CTX regularly followed at six genetics reference centers in Brazil between March 2020 and August 2023. We evaluated 38 CTX patients from 26 families, originating from 4 different geographical regions in Brazil. Genetic analysis identified 13 variants in the CYP27A1 gene within our population, including 3 variants that had not been previously described. The most frequent initial symptom of CTX in Brazil was cataract (27%), followed by xanthomas (24%), chronic diarrhea (13.5%), and developmental delay (13.5%). We observed that the median age at loss of ambulation correlates with the age of onset of neurological symptoms, with an average interval of 10 years (interquartile range 6.9 to 11 years). This study represents the largest CTX case series ever reported in South America. We describe phenotypic characteristics and report three new pathogenic or likely pathogenic variants.

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.

Case Report: a novel CYP27A1 gene variant in a patient with cerebrotendinous xanthomatosis with unusual clinical findings.

PURPOSE/AIM OF THE STUDY: Cerebrotendinous xanthomatosis is a disease with important clinical and molecular heterogeneity. CYP27A1 gene was described as the cause of these defects, with more than 50 mutations involved in the disease. The objective of this study was to carry out a genetic study and a clinical description of a patient with unusual clinical manifestation of the disease. MATERIALS AND METHODS: DNA sequencing was used for the evaluation of CYP27A1 exon sequences and their intron/exon boundaries. Copy number variants were calculated using a method based on depth of sequencing coverage. In addition, the potential effects of the missense variants were analyzed, and an in-silico protein modeling tool was used. Finally, a patient case description was performed in order to evaluate patient phenotype according to genetic results. RESULTS: Patient clinical features indicate the possible presence of a disease milder phenotype. When analyzing the CYP27A1 gene, patient presents a pathogenic variant (p.Arg474Trp) and a variant of unknown significance (p.Met130Ile) that causes a slight modification of the protein functional structure. This variant in homozygosis or double or compound heterozygosis together with other biallelic pathological mutations may be the cause of the clinical phenotype observed in the reported patient. CONCLUSIONS: Clinical manifestations of cerebrotendinous xanthomatosis are heterogeneous, and sometimes wrongly suggest the presence of other diseases. Some patients seem to present an "incomplete" phenotype, which could be redefined as a variant of the disease with further studies. The evaluation of new mutations allows for earlier diagnosis and greater effectiveness in its treatment.

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.

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.

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.

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. .

Liver transplantation in an infant with cerebrotendinous xanthomatosis, cholestasis, and rapid evolution of liver failure.

BACKGROUND: Cerebrotendinous xanthomatosis (CTX) is a disorder of bile acid (BA) metabolism due to biallelic mutations in CYP27A1. The deposition of cholesterol and cholestanol in multiple tissues results, manifesting as neurologic disease in adults or older children. Neonatal cholestasis (NC) as a presentation of CTX is rare; it may self-resolve or persist, evolving to require liver transplantation (LT). METHODS: We present in the context of similar reports an instance of CTX manifest as NC and requiring LT. RESULTS: A girl aged 4mo was evaluated for NC with normal serum gamma-glutamyl transpeptidase activity. An extensive diagnostic work-up, including liver biopsy, identified no etiology. Rapid progression to end-stage liver disease required LT aged 5mo. The explanted liver showed hepatocyte loss and micronodular cirrhosis. Bile salt export pump (BSEP), encoded by ABCB11, was not demonstrable immunohistochemically. Both severe ABCB11 disease and NR1H4 disease-NR1H4 encodes farsenoid-X receptor, necessary for ABCB11 transcription-were considered. However, selected liver disorder panel sequencing and mass-spectrometry urinary BA profiling identified CTX, with homozygosity for the predictedly pathogenic CYP27A1 variant c.646G > C p.(Ala216Pro). Variation in other genes associated with intrahepatic cholestasis was not detected. Immunohistochemical study of the liver-biopsy specimen found marked deficiency of CYP27A1 expression; BSEP expression was unremarkable. Aged 2y, the girl is free from neurologic disease. CONCLUSIONS: Bile acid synthesis disorders should be routinely included in the NC/"neonatal hepatitis" work-up. The mutually supportive triple approach of BA profiling, immunohistochemical study, and genetic analysis may optimally address diagnosis in CTX, a treatable disease with widely varying presentation.

Cerebrotendinous xanthomatosis without neurological involvement.

BACKGROUND: Cerebrotendinous xanthomatosis (CTX) is an autosomal recessively inherited inborn error of metabolism. Neurological symptoms are considered to be a clinical hallmark of untreated adult patients. We describe a 'milder CTX phenotype', without neurological involvement. METHODS: We performed a retrospective patient file study in 79 genetically confirmed Dutch patients with CTX (55 patients aged ≥ 21 years) to study the clinical heterogeneity of CTX. We studied the frequency of adult patients with CTX without neurological involvement at diagnosis, in our Dutch cohort, and included a family from South Africa and patients from Italy, USA, Chile and Asia from the literature. RESULTS: In total, we describe 19 adult patients with CTX from 16 independent families, without neurological symptoms at diagnosis. A relatively small percentage (21%, n = 4) had a history of cataract. The majority, 84% (n = 16), presented with tendon xanthomas as the sole or predominant feature. The majority of patients showed increased plasma cholesterol levels. No correlation was found between this 'milder phenotype', the cholestanol levels and the CYP27A1 genotype. In addition, we describe three novel mutations in the CYP27A1 gene. CONCLUSIONS: This study shows the clinical heterogeneity of CTX, highlighting the existence of a 'milder phenotype', that is without neurological involvement at diagnosis. Adult patients with CTX may present with tendon xanthomas as the sole or predominant feature, mimicking familial hypercholesterolemia. It is important to realize that the absence of neurological symptoms does not rule out the development of future neurological symptoms. As CTX is a treatable disorder, early diagnosis and initiation of treatment when additional clinical signs occur is therefore essential.

Patients with cerebrotendinous xanthomatosis diagnosed with diverse multisystem involvement.

Cerebrotendinous xanthomatosis (CTX) is a lipid storage disease caused by deficiency of sterol 27-hydroxylase enzyme encoded by CYP27A1 gene. This multicenter, cross-sectional descriptive study aimed to document clinical characteristics of CTX patients of different ages, clinical presentations of early-diagnosed patients, and responses to short-term chenodeoxycholic acid (CDCA) treatment. Seven of 11 CTX patients were diagnosed in childhood. Three patients (27%) had neonatal cholestasis, seven (63%) patients had a history of frequent watery defecation started in infantile period, and eight (72.7%) patients had juvenile cataract. Four patients in the adult age group had pyramidal signs and parkinsonism symptoms. The mean Mignarri score at diagnosis was significantly lower in the pediatric patients (267.8 ± 51.4) than in the adult patients (450.0 ± 64.0, p = 0.001). No significant difference was determined between pediatric patients and adult patients regarding plasma cholestanol concentration at diagnosis (p = 0.482). The frequency of defecation decreased with treatment in six children, who had diarrhea at admission. Compared to pretreatment values, patients' body weight and standardized body mass index significantly increased at the 12th month of treatment. In conclusion, Mignarri scores are lower in the pediatric patients than in adult patients since the most determinative signs of the CTX disease are not apparent yet in the childhood. The disease is frequently overlooked in routine practice as the disease presents itself with different clinical combinations both in adults and in children. CTX is potentially a treatable disease; thereby, enhanced awareness is critically important for early diagnosis particularly in children.

Toward newborn screening of cerebrotendinous xanthomatosis: results of a biomarker research study using 32,000 newborn dried blood spots.

PURPOSE: Cerebrotendinous xanthomatosis (CTX) is a treatable hereditary disorder caused by the deficiency of sterol 27-hydroxylase, which is encoded by the CYP27A1 gene. Different newborn screening biomarkers for CTX have been described, including 7α,12α-dihydroxy-4-cholesten-3-one (7α12αC4), 5ß-cholestane-3α,7α,12α,25-tetrol glucuronide (GlcA-tetrol), the ratio of GlcA-tetrol to tauro-chenodeoxycholic acid (t-CDCA) (GlcA-tetrol/t-CDCA), and the ratio of tauro-trihydroxycholestanoic acid (t-THCA) to GlcA-tetrol (t-THCA/GlcA-tetrol). We set out to evaluate these screening methods in a research study using over 32,000 newborn dried blood spots (DBS). METHODS: Metabolites were extracted from DBS with methanol containing internal standard, which was then quantified by ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). RESULTS: The measurement of 7α12αC4 was complicated by isobaric interferences and was discontinued. A total of 32,737 newborns were screened based on the GlcA-tetrol concentration in DBS. GlcA-tetrol/t-CDCA and t-THCA/GlcA-tetrol ratios were also calculated. Newborns displaying both elevated GlcA-tetrol and GlcA-tetrol/t-CDCA ratio were considered to be screen positives. The t-THCA/GlcA-tetrol ratio was used to further distinguish CTX screen positives from Zellweger Spectrum Disorder (ZSD) screen positives. Only one newborn displayed both elevated GlcA-tetrol concentration in DBS and a typical CTX biochemical profile. This newborn was interpreted as a CTX-affected patient as CYP27A1 gene sequencing identified two known pathogenic variants. CONCLUSION: The results indicate that both GlcA-tetrol and the GlcA-tetrol/t-CDCA ratio are excellent CTX biomarkers suitable for newborn screening. By characterizing the relationship of GlcA-tetrol, t-CDCA, and t-THCA as secondary markers, 100% assay specificity can be achieved.

Misdiagnosis of CTX due to propofol: The interference of total intravenous propofol anaesthesia with bile acid profiling.

BACKGROUND: Cerebrotendinous xanthomatosis (CTX) is a rare genetic disorder, characterised by chronic diarrhoea, xanthomas, cataracts, and neurological deterioration. CTX is caused by CYP27A1 deficiency, which leads to abnormal cholesterol and bile acid metabolism. Urinary bile acid profiling (increased m/z 627: glucuronide-5ß-cholestane-pentol) serves as diagnostic screening for CTX. However, this led to a false positive CTX diagnosis in two patients, who had received total intravenous anaesthesia (TIVA) with propofol. METHODS: To determine the influence of propofol on bile acid profiling, 10 urinary samples and 2 blood samples were collected after TIVA with propofol Fresenius 7 to 10 mg/kg/h from 12 subjects undergoing scoliosis correction. Urinary bile acids were analysed using flow injection negative electrospray mass spectrometry. Propofol binding to recombinant CYP27A1, the effects of propofol on recombinant CYP27A1 activity, and CYP27A1 expression in liver organoids were investigated using spectral binding, enzyme activity assays, and qPCR, respectively. Accurate masses were determined with high-resolution mass spectrometry. RESULTS: Abnormal urinary profiles were identified in all subjects after TIVA, with a trend correlating propofol dose per kilogramme and m/z 627 peak intensity. Propofol only induced a weak CYP27A1 response in the spectral binding assay, minimally affected CYP27A1 activity and did not affect CYP27A1 expression. The accurate mass of m/z 627 induced by propofol differed >10 PPM from m/z 627 observed in CTX. CONCLUSIONS: TIVA with propofol invariably led to a urinary profile misleadingly suggestive of CTX, but not through CYP27A1 inhibition. To avoid further misdiagnoses, propofol administration should be considered when interpreting urinary bile acid profiles.

A Neuropsychological Profile for Cerebrotendinous Xanthomatosis: A Single-Case Study.

OBJECTIVE: Cerebrotendinous xanthomatosis (CTX) belongs to a heterogeneous group of neurological disorders known as autosomal recessive cerebellar ataxias. Low awareness of CTX can result in misdiagnoses in the differential diagnostic process and may limit one's ability to offer suitable recommendations. While neurodegeneration is a recognized manifestation of CTX, there is scant literature to characterize the nature of cortical symptoms and even less detailing of its associated neurocognitive and neuropsychiatric manifestations. METHOD: Based on the lack of representation of CTX in neuropsychological literature, we sought to present a case seen in a 39-year-old patient within our own clinic. RESULTS: Evaluation of the patient's neurocognitive functioning revealed global impairment consistent with a CTX diagnosis and neuroimaging findings noting significant cerebellar involvement. CONCLUSIONS: Neuropsychologists are increasingly called upon to make treatment recommendations and provide information that may be helpful in differential diagnosis as part of multidisciplinary teams. Referrals from neurology are common, and it is important for neuropsychologists to be aware of diseases that affect the central nervous system; CTX is one such example. The goal of this case study is to build awareness of this condition and increase interest in a more systematic approach to research and clinical care of this population.

The safety and effectiveness of chenodeoxycholic acid treatment in patients with cerebrotendinous xanthomatosis: two retrospective cohort studies.

OBJECTIVE: To evaluate the safety and effectiveness of chenodeoxycholic acid (CDCA) treatment in patients with cerebrotendinous xanthomatosis (CTX). METHODS: Two retrospective cohort studies were conducted in CTX patients who underwent CDCA treatment: one in the Netherlands (NL; CDCA-STUK-15-001) and one in Italy (IT; CDCA-STRCH-CR-14-001). Eligible patients were aged 2-75 years, had been diagnosed with CTX, and were treated with CDCA orally for ≥1 year. The impact of CDCA treatment on biochemical markers (including serum cholestanol levels) and disease signs and symptoms were assessed, in addition to the safety and tolerability of CDCA treatment. RESULTS: A total of 35 patients were screened in the NL study and were diagnosed with CTX at 25.6 (± 13.7 SD) years on average. These patients were treated with CDCA and followed up for a median of 9.00 (range: 0.4-26.3) years. In addition, 28 patients were enrolled in the IT study and were diagnosed at 35.0 (± 11.4 SD) years on average (median duration of CDCA treatment: 5.75 [range: 0.0-25.0] years). Signs and symptoms of disease resolved, improved, or remained stable in many patients, with concomitant improvements in biochemical marker levels (serum cholestanol, p < 0.001; 7α-hydroxy-4-cholesten-3-one, p < 0.001 [IT study]). CONCLUSIONS: The outcomes of these retrospective cohort studies indicate that CDCA is effective in the long-term treatment of CTX, with an acceptable safety profile.

A novel mutation in the CYP27A1 gene in a family with cerebrotendinous xanthomatosis.

PURPOSE OF THE STUDY: Cerebrotendinous xanthomatosis (CTX) is an inherited disorder associated with abnormal deposition of cholestenol in the brain and other tissues. Here we report a Chinese family with two affected members of CTX. MATERIALS AND METHODS: Clinical data were collected. Gene analysis, MRI, neuropsychological assessments, and the biopsy of right Achilles tendon xanthoma were carried out. RESULTS: The two cases had similar symptoms for cataracts, chronic diarrhea, progressive cognitive impairment and a disturbance of gait, and were identified with the same compound heterozygous mutations, c.435G>T in exon 2 and c.562C>T in exon 3. CONCLUSIONS: Cerebrotendinous xanthomatosis (CTX) is an inherited disorder associated with abnormal deposition of cholestenol in the brain and other tissues. Although CTX is a treatable disease, the time of beginning treatment is crucial for therapeutic effect. Unfortunately, it usually takes years even decades from initial symptoms to the diagnosis of CTX. The screening for 27-hydroxylase (CYP27A1) gene even before the occurrence of tendon xanthoma is important for early diagnosis.

Age-related changes of cholestanol and lathosterol plasma concentrations: an explorative study.

BACKGROUND: Cerebrotendinous xanthomatosis (CTX) and Lathosterolosis represent two treatable inherited disorders of cholesterol metabolism that are characterized by the accumulation of cholestanol and lathosterol, respectively. The age of the patients suspected of having these disorders is highly variable due to the very different phenotypes. The early diagnosis of these disorders is important because specific therapeutic treatment could prevent the disease progression. The biochemical diagnosis of these defects is generally performed analyzing the sterol profile. Since age-related levels of these sterols are lacking, this study aims to determine a preliminary comparison of plasma levels of cholestanol and lathosterol among Italian unaffected newborns, children and healthy adults. METHODS: The sterols were extracted from 130 plasma samples (24 newborns, 33 children and 73 adults) by a liquid-liquid separation method and quantified by gas chromatography coupled with a flame ionization detector. RESULTS: Cholesterol, cholestanol and lathosterol levels together with the cholestanol/cholesterol and lathosterol/cholesterol ratios are statistically different among the three groups. Cholesterol levels progressively increased from newborns to children and to adults, whereas cholestanol/cholesterol and cholestanol/lathosterol ratios progressively decreased from newborns to children and to adults. Lathosterol levels were higher in adults than in both newborns and children. In the total population a positive correlation was observed between cholesterol levels and both cholestanol (correlation coefficient = 0.290, p = 0.001) and lathosterol levels (correlation coefficient = 0.353, p <  0.0001). CONCLUSIONS: Although this study can only be considered an explorative experience due to the low number of analyzed samples, we revealed several differences of plasma cholestanol and lathosterol levels and their ratios to cholesterol levels among newborns, children and adults. These evidences indicate the need of age-related reference values of cholestanol and lathosterol concentrations, including also newborns and children.

Patients with Lately Diagnosed Cerebrotendinous Xanthomatosis.

OBJECTIVES: Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive inborn lipid storage disorder due to various pathogenic mutations in the CYP27A1 gene. Although the symptoms begin commonly in infancy, CTX diagnosis is often delayed. In this study, we report 7 Turkish CTX patients who had a delayed diagnosis despite early clinical signs and belonged to 6 unrelated families. METHODS: We have retrospectively evaluated clinical, laboratory, imaging, and genetic findings of CTX patients, which were collected from 2 centers specialized in movement disorders: the Department of Neurology, Faculty of Medicine, Istanbul University, and the Department of Neurology, Faculty of Medicine, Mersin University. RESULTS: All patients were diagnosed with CTX after neurological symptom development, and their mean age at diagnosis was 38.7 ± 9.6 years, despite a mean onset age of 12.4 ± 10.6 years. The mean follow-up period was 28 months (range: 3-60 months). The most common initial clinical abnormalities in our cohort were unexplained chronic diarrhea (42%), febrile convulsion (42%), juvenile cataract (85%), childhood depression and autism (14%), parkinsonism (14%), and intellectual disability (100%). The most prominent neurological findings were the pyramidal-cerebellar syndrome (85%) and extrapyramidal signs (42%). All patients were genetically confirmed. Serum cholestanol levels were elevated in all patients and decreased after chenodeoxycholic acid (CDCA) treatment in 6 patients. CONCLUSION: This cohort is the largest CTX case series in Turkey. All cases showed improvement in gastrointestinal symptoms as a response to CDCA treatment and stabilization on neurological symptoms, i.e., no further progression of neurological abnormalities were noted during this treatment. Therefore, early diagnosis and treatment is crucial in preventing clinical deterioration.

Natural history of neurological abnormalities in cerebrotendinous xanthomatosis.

OBJECTIVES: Cerebrotendinous xanthomatosis (CTX) is a rare inherited neurodegenerative disorder in bile acid synthesis. The natural history of neurological abnormalities in CTX is not well understood. The object of this study was to determine neurological progression in CTX. METHODS: A literature search on PubMed for "cerebrotendinous xanthomatosis" yielded 91 publications that reported cases of CTX patients. Two independent reviewers abstracted information about the presence and age of onset of neurological abnormalities in published CTX cases. For each neurological abnormality, we estimated the probability of its onset at any given age using cumulative incidence function analysis. We also present our own case series, in which five CTX patients were evaluated. RESULTS: The literature search yielded 194 CTX cases (ages ranging from newborn to 67 years old). The most common neurological abnormalities were corticospinal tract abnormalities including weakness, hyperreflexia, spasticity, Babinski sign (59.8%), ataxia (58.8%), cognitive decline (46.4%), and gait difficulty (38.1%); 68 (35.0%) had baseline cognitive problems. Cumulative incidence function analysis revealed that ataxia, gait difficulties, and corticospinal tract abnormalities developed throughout life, while cognitive decline tended to develop later in life. Of the less common neurological abnormalities, seizures, psychiatric changes and speech changes developed throughout life, while parkinsonism and sensory changes tended to develop later in life. Our case series corroborated this temporal pattern of neurological abnormalities. CONCLUSION: We provide estimates for the neurological progression of CTX, categorizing neurological abnormalities according to time and probability of development. Our approach may be applicable to other rare disorders.

Clinical report: A patient with a late diagnosis of cerebrotendinous xanthomatosis and a response to treatment.

Cerebrotendinous xanthomatosis (CTX) is a rare, autosomal recessive, inborn error of bile acid metabolism characterized by diarrhea in infancy, juvenile cataracts in childhood, tendon xanthomas developing in the second to third decades of life, and progressive neurologic dysfunction in adulthood. The condition is caused by mutations in the CYP27A1 gene that result in decreased production of chenodeoxycholic acid (CDCA) and elevated levels of cholestanol and bile alcohols. We present a 36-year-old male of Han ethnicity who developed xanthomas of his Achilles tendons and suffered neurocognitive declines and gait deterioration in his second decade. The diagnosis of CTX was confirmed by marked elevation of the serum cholestanol level. Sequencing of CYP27A1 showed a paternally inherited splice mutation, c.446 + 1G>T, and a maternally inherited nonsense mutation, c.808C>T, predicting p.(Arg270*). Despite the advanced disease in this patient, treatment with CDCA reduced the xanthoma size and improved his cognition and strength, and the patient made significant gains in his ambulation and coordination. We report this case to illustrate the potential benefits of therapy in patients with CTX who have advanced disease at the time of diagnosis.