Clinical and Imaging Profile of Patients with Cerebrotendinous Xanthomatosis - a Video Case Series from India.

Background: Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disorder caused by bi-allelic pathogenic variants in CYP27A1 gene that results in the deposition of cholestanol in the eyes, tendons, soft tissues and nervous system leading to cataracts, xanthomas, and various neuropsychiatric manifestations. The aim of our study is to describe the clinical, radiological and genetic profile of patients with CTX. Methods: This is a retrospective chart review of patients with CTX diagnosed based on classical clinical and radiological findings. The available clinical details, and investigations, including imaging, electrophysiological, pathological and genetic data, were documented. Results: Five patients (4 males) were recruited in the study. The median age at presentation was 32 years (range: 21-66 years). Walking difficulty was the most common symptom at presentation. All patients had cataracts, tendon xanthomas, eye movement abnormalities, dysarthria, pyramidal signs, ataxia and gait abnormality. Dystonia was noted in three patients. Palatal tremor and parkinsonism were noted in one patient each. In MRI brain, dentate, and corticospinal tract involvement were the most frequent imaging findings. Bilateral hypertrophic olivary degeneration was noted in one patient and hot cross bun sign in two. Three patients underwent genetic testing and all had pathogenic variants confirming the diagnosis. Discussion: CTX is a rare treatable disorder. Apart from the usual neurological presentation with spastic-ataxia, it can present at a later age with parkinsonism. Typical patterns of imaging findings are helpful in early diagnosis which aids in the treatment to prevent the neurological sequelae of the disease.

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.

Cerebrotendinous Xanthomatosis patients with late diagnosed in single orthopedic clinic: two novel variants in the CYP27A1 gene.

BACKGROUND: Cerebrotendinous Xanthomatosis (CTX) is a rare autosomal recessive lipid storage disorder caused by loss of function variants in the CYP27A1 gene which encodes sterol 27-hydroxylase, on chromosome 2q35. Although the symptoms begin commonly in infancy, CTX diagnosis is often delayed. The aim of this study is to review the orthopedic findings of the disease by providing an overview of the clinical features of the disease. It is to raise awareness of this condition for which early diagnosis and treatment are important. METHODS: We retrospectively evaluated the clinical, laboratory, radiological, and genetic findings of eight patients from four families who were admitted to our Orthopedics and Traumatology Department between 2017 and 2022 due to bilateral Achilles tendon xanthomas, were found to have high cholestanol and CYP27A1 gene mutations. RESULTS: The mean age of patients was 37, and five of them were male. The mean age at the onset of symptoms was 9.25 years. The mean age of initial diagnosis was 33.75 years. Between symptom onset and clinical diagnosis, an average delay of 24.5 years was observed. All patients had bilateral Achilles tendon xanthoma. Notably, a novel variant (c.670_671delAA) in CYP27A1 gene was identified in three patients who also presented with peripheral neuropathy and bilateral pes cavus. One patient had osteoporosis and four patients had osteopenia. Five patients had a history of bilateral cataracts. Furthermore, three of the patients had early-onset chronic diarrhea and three of the patients had ataxia. Two of the patients had epilepsy and seven of the patients had behavior-personality disorder. All patients had low intelligence, but none of them had cardiac disease. CONCLUSION: We present the diagnostic process and clinical features which the largest CTX case series ever reported from single orthopedic clinic. We suggest that patients with normal cholesterol levels presenting with xanthoma being genetically analyzed by testing at their serum cholestanol level, and that all siblings of patients diagnosed with CTX be examined.

Identification of pathogenic genetic variants in patients with acquired early-onset bilateral cataracts using next-generation sequencing.

BACKGROUND: Acquired early-onset bilateral cataracts can result from systemic etiologies or genetic disorders. METHODS: In this observational study, we analyzed individuals 18 months to 35 years of age with acquired bilateral cataracts via a next-generation sequencing panel of 66 genes to identify disease-causing genetic variants. RESULTS: Of 347 patients enrolled, 313 (90.2%) were <19 years (median, 8 years). We identified 74 pathogenic or likely pathogenic variants in 69 patients. Of the variants, we observed 64 single nucleotide variants (SNV) in 24 genes and 10 copy number variants (CNV) of varying size and genomic location. SNVs in crystallin genes were most common, accounting for 27.0% of all variants (20 of 74). Of those, recurrent variants included known cataract-causing variants CRYBA1 c.215+1G>A, observed in 3 patients, and CRYBA1 c.272_274delGAG, CRYBB2 c.463C>T and c.562C>T, and CRYAA c.62G>A, each observed in 2 patients. In 5 patients, we identified CNV deletions ranging from 1.32-2.41 Mb in size associated with 1q21.1 microdeletion syndrome. Biallelic variants in CYP27A1 were identified in two siblings, one as part of targeted follow-up family testing, who were subsequently diagnosed with cerebrotendinous xanthomatosis, a rare but treatable autosomal recessive disease that often presents with acquired early-onset bilateral cataracts. CONCLUSIONS: This study demonstrates the utility of genetic testing in individuals with acquired early-onset bilateral cataracts to help clarify etiology. Identification of causative genetic variants can inform patient management and facilitate genetic counseling by identifying genetic conditions with risk of recurrence in families.

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.

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.

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.

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.

Early diagnosis for cerebrotendinous xanthomatosis with juvenile cataract and family history.

PURPOSE: Cerebrotendinous xanthomatosis is characterized by excessive accumulation of cholestanol and cholesterol in multiple tissues including the brain, tendons, and the crystalline lens. Since juvenile cataract is the most common and early pathognomonic feature of this disease, it is critical to analyze some factors such as family history, systemic findings, and cataract morphology in children with cataracts. This study aims to report the early diagnosis of cerebrotendinous xanthomatosis in four siblings presenting with unique juvenile cataracts from a family with consanguineous marriage. METHODS: This is a retrospective noncomparative case series. Four symptomatic siblings and their asymptomatic parents were examined. Detailed eye examination, medical history analysis, evaluation of systemic findings, biochemical tests, and mutation analysis were performed. RESULTS: While one sister presented with bilateral fleck-like opacities and posterior subcapsular cataract, two twin sisters had anterior star-shaped sutural cataract and posterior subcapsular cataract besides bilateral fleck-like opacities. The 20-year-old brother who had previously died in a traffic accident had bilateral juvenile cataract of unknown morphology. When asked specifically, none of the cases described a history of childhood diarrhea. Two sisters and one brother had neurological findings such as trouble walking and slowed speech. No significant ocular or systemic finding was found in both asymptomatic parents. Homozygous c.1263 + 1 G>A (intron 7) mutation was detected in the CYP27A1 gene in all symptomatic cases. CONCLUSION: In the absence of chronic diarrhea, the presence of juvenile cataract (especially bilateral fleck-like opacities), neurological symptoms in the family history, and consanguinity of the parents might be considerably helpful for the early diagnosis of cerebrotendinous xanthomatosis.

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.

[Clinical and genetics characteristics of adult-onset cerebrotendinous xanthomatosis: analysis of a Chinese pedigree].

Objective: Clinical manifestations, imaging findings, pathologic features, and genetic mutations of Chinese adult patients with cerebrotendinous xanthomatosis (CTX) were analyzed in order to achieve a greater understanding of CTX that can improve early detection, diagnosis, and treatment. Methods: Clinical data including medical history, neurologic and auxiliary examinations, imaging findings, and genetic profile were collected for an adult patient with CTX admitted to the Sixth Medical Center of Chinese People's Liberation Army General Hospital in August 2020. Additionally, a systematic review of genetically diagnosed Chinese adult CTX cases reported in major databases in China and other countries was performed and age of onset, first symptoms, common signs and symptoms, pathologic findings, imaging changes, and gene mutations were analyzed. Results: The proband was a 39-year-old female with extensive, early-onset nervous system manifestations including cognitive dysfunction and ataxia. Systemic lesions included juvenile cataract and a tendon mass. Cranial magnetic resonance imaging revealed cerebral atrophy, symmetric white matter changes predominantly in the pyramidal tract, and lesions in the cerebellar dentate nucleus. A novel homozygous mutation in the sterol-27-hydroxylase (CYP27A1) gene (c.1477-2A>C) was identified. There were no family members with similar clinical presentation although some were carriers of the c.1477-2A>C mutation. The patient showed a good response to deoxycholic acid treatment. Totally there were 56 cases of adult CTX patients in China, mostly in East China (31/56, 55.4%), at a male-to-female ratio of 1.8 to 1. Multiple organs and tissues including nervous system, tendon, lens, lung, and skeletal muscle were affected in these cases. The most common neurologic manifestations were cognitive dysfunction (44/52, 84.6%) and ataxia (44/51, 86.3%). The cases were characterized by early onset, chronic progressive damage of multiple systems, long disease course, and delayed diagnosis, making the disease difficult to manage clinically and resulting in poor prognosis. The 2 most common genetic mutations in Chinese adult CTX patients were c.1263+1G>A and c.379C>T. Exon 2 of the CYP27A1 gene was identified as a mutation hot spot. Conclusions: Chinese adult patients with CTX have complex clinical characteristics, a long diagnostic cycle, and various CYP27A1 gene mutations. Early diagnosis and intervention can improve the prognosis of these patients.

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.

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.

A case of cerebrotendinous xanthomatosis with brain and spinal involvement without tendon xanthomas: Identification of a novel mutation of the CYP27A1 gene.

Cerebrotendinous xanthomatosis (CTX) is a rare inherited disorder of the alternative pathway of bile acid biosynthesis, due to mutation(s) of the gene CYP27A1, leading to sterol 27-hydroxylase deficiency. The latter results in a systematic deposition of cholestanol and cholesterol to the central nervous system and tendons, premature cataract, as well as the manifestation of systematic symptoms, such as chronic diarrhea, osteoporosis, and premature atherosclerosis. Due to its marked clinical heterogeneity, prompt diagnosis of this disorder is challenging. We present a case of a 38-year-old male with gait difficulty, a progressive deterioration in ambulation, several episodes of vertigo and episodic diarrhea. Clinical history revealed neonatal jaundice, juvenile bilateral cataracts, borderline intellectual capacity, hypothyroidism, testicular cancer. Magnetic resonance imaging demonstrated increased T2-weighted signal in internal capsules, midbrain, cerebellum, and spinal cord. Electrodiagnostic study showed mixed polyneuropathy. Genetic analysis revealed a novel, biallelic, most likely pathogenic mutation, in gene CYP2A1 (c.1410_1411del). Plasma sterol profiling confirmed the diagnosis of CTX. Our patient was treated with chenodeoxycholic acid and one year later, he shows a progressive improvement of gait, normalization of plasma sterol biochemistry and electrophysiological parameters. This case highlights the importance of maintaining a high index of suspicion as the key to an early diagnosis of CTX, taking into consideration its clinical variability and, if promptly identified, the good response to treatment.

Xantomatose cerebrotendínea: uma doença rara e multissistêmica ainda pouco conhecida. Quando devemos suspeitar? / Cerebrotendinous xanthomatosis: a rare and multisystemic disease still little known. When should we suspect?

Xantomatose cerebrotendínea (XCT) é uma doença congênita autossômica recessiva rara multissistêmica do me-tabolismo do ácido biliar que leva ao acúmulo de intermediários do colesterol em diversos tecidos. A principal ma-nifestação da doença é o acometimento neurológico progressivo e irreversível, que inicia na infância e evolui com disfunção neurológica grave na fase adulta. Sintomas não neurológicos característicos como xantomas tendíneos, cataratas de início na infância e diarreia crônica infantil também podem estar presentes. No Brasil, não existe te-rapia medicamentosa para a doença. A principal abordagem terapêutica para retardar a progressão do quadro é o acompanhamento multidisciplinar com o objetivo de melhorar a qualidade de vida. Apesar dos sintomas iniciarem na infância, a maioria dos pacientes demora em média 16 anos para receber o diagnóstico, fase na qual o dano neurológico já é extenso e as abordagens terapêuticas não são mais eficazes. Neste estudo é relatado o caso de paciente de 47 anos com XCT que iniciou os sintomas na infância, com piora neurológica aos 38 anos e diagnóstico aos 44 anos, fase na qual a neurodegeneração já era grave e irreversível. Os testes laboratoriais e Imagem de Res-sonância Magnética indicaram alterações características da doença. Ressalta-se a importância de ter a XTC como diagnóstico diferencial na presença de um quadro neurológico progressivo, amplo e variado, associado com xanto-mas tendíneos e outros sinais e sintomas específicos. Por tratar-se de doença crônica e degenerativa, o diagnóstico precoce é essencial para que se possa instituir medidas que melhorem a qualidade de vida (AU)

Cerebrotendinous xanthomatosis (CTX) is a rare, multisystemic autosomal-recessive disease of biliary acid me-tabolism that leads to accumulation of cholesterol intermediates in multiple tissues. Its primary presentation is progressive and irreversible neurological damage, beginning in childhood and progressing to neurological dys-function in adulthood. There also are characteristic non-neurological symptoms, including tendinous xanthomas, cataracts beginning in childhood, and chronic infantile diarrhea. In Brazil, there is no available treatment for CTX. The primary therapeutic approach to slow disease progression is a palliative one, with multidisciplinary team. While CTX symptoms begin in childhood, most patients are diagnosed at approximately age 16, when neurological damage is extensive and therapeutic approaches are no longer effective. Here, we report a case of a 47-year-old female patient with CTX with symptoms beginning in childhood, with neurological worsening at the age of 38 and diagnosis at 44, at which neurodegeneration was already severe and irreversible. Laboratory tests and magnetic resonance imaging indicated characteristic symptoms. It is important to consider CTX as a differential diagnosis in the presence of a progressive, wide, and varied neurological picture, with tendinous xanthomas and other specific symptoms. Because it is a chronic and degenerative disease, early diagnosis is essential to establish measures to improve the quality of life (AU)

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. .

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.

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.